Treasury Secretary Scott Bessent will skip a meeting of finance ministers and central bankers from the Group of 20 nations in Cape Town next week, according to people familiar with his plans, deepening the rift between the United States and South Africa over policies the Trump administration believes are anti-American.

The decision to forgo such a major economic gathering is highly unusual for a Treasury secretary, particularly one who was confirmed to his post three weeks ago. It comes at a pivotal moment for the global economy, as the United States moves toward imposing tariffs on virtually all of its trading partners. President Trump is also seeking deeper economic ties with Russia, an adversary that the United States was aligned against in coordination with Western allies until he returned to office.

Mr. Bessent’s decision came after a boycott of a similar meeting this week of foreign ministers in Johannesburg by Secretary of State Marco Rubio. Mr. Rubio said he was skipping the gathering because he did not want to “waste taxpayer money or coddle anti-Americanism.”

Mr. Trump has indicated that he sees little value in multilateral meetings like the Group of 20 and prefers to hold bilateral negotiations with other nations. The theme for the meetings this year is “solidarity, equality, sustainability,” which the administration considers at odds with its views on climate change and diversity policies.

The gathering would have been Mr. Bessent’s first opportunity to meet with his global counterparts and have talks with top financial officials from Europe, China and Russia.

Mark Sobel, who served at the Treasury Department for nearly four decades, called the decision to skip the meetings a “colossal mistake.” He noted that such gatherings were an opportunity for the Trump administration to lay out its global priorities and discuss the state of the world economy and central issues such as exchange rates.

“The Trump administration and Scott Bessent are thumbing their noses at the international economic and financial system,” Mr. Sobel said. “That will not make America greater or safer.”

The G20 was created in 1999 after the Asian Financial Crisis as a forum for finance ministers and central bankers to meet and discuss international economic matters and financial stability.

The group’s meetings have been awkward in recent years because of tension between Russia and Western allies, including the United States, over the war in Ukraine. But the Trump administration has made clear that it intends to take a different approach with Russia as it looks to negotiate an end to the war.

Mr. Trump suggested this week that Ukraine might have been responsible for Russia’s invasion and on Wednesday referred to the Ukrainian president, Volodymyr Zelensky, on social media as a “Dictator without Elections.”

The decision by Mr. Bessent not to attend the meetings will come as a disappointment and a surprise to South Africa. An official from its Department of International Relations and Cooperation posted on social media this week that the Treasury secretary was expected to attend the meetings in Cape Town.

A spokeswoman for Mr. Bessent had no comment on Wednesday.

Another person familiar with the situation said that Mr. Bessent was in regular contact with his international counterparts and opted to stay in the United States next week to focus on domestic matters. A senior Treasury official will be attending the meetings in his place, the person said.

The diplomatic tension between the United States and South Africa emerged as a surprising turn of events this year.

Earlier this month, Mr. Trump ordered that all foreign assistance to South Africa be halted and said his administration would prioritize the resettling of white, “Afrikaner refugees” into the United States because of what he called actions by the country’s government that “racially disfavored landowners.”

Mr. Trump’s recent comments were in reference to a policy that President Cyril Ramaphosa of South Africa signed into law last month.

Known as the Expropriation Act, the law repeals an apartheid-era policy and allows the government in certain instances to acquire privately held land in the public interest without paying compensation. This can be done only after a justification process subject to judicial review.

An Israeli military prosecutor charged five reservist soldiers on Wednesday with abuse of a Palestinian detainee, saying it took place last year at a military base where thousands of Gazans have been held.

The indictment accused soldiers at the Sde Teiman base in southern Israel of breaking the detainee’s ribs, puncturing his left lung and tearing his rectum. The detainee was identified only by his initials.

Avi Amiram and Lior Porat, lawyers representing one of the soldiers, said they have presented arguments that deny the charges against the reservists. Honenu, a right-wing legal organization representing two of the soldiers, criticized the charges and claimed the detainee was a militant in an elite unit in the northern Gaza Strip. The New York Times could not independently verify Honenu’s allegation about the detainee.

The indictment contains some of the most serious allegations of mistreatment at Sde Teiman since the Israeli military launched its offensive in Gaza in the aftermath of the Hamas-led October 2023 attack on Israel. The case against the soldiers has also revealed divisions in Israel about the extent to which soldiers should be held accountable for abusing Palestinian detainees accused of involvement in terrorist activity.

On the evening of July 5, 2024, soldiers beat the detainee while he screamed in pain, according to the indictment, which said his hands and legs were bound and his eyes blindfolded.

“For about 15 minutes, the defendants hit the detainee, stomped on him, and stood on his body,” the document said. “They struck him all over his body.”

Soldiers also used a Taser against him, including on his head, the prosecutor’s account said. At one point, one of the soldiers stabbed him with a “sharp object,” causing a tear in his rectal wall, it added.

Hours later, medics rushed the detainee to a health clinic at the base, where a doctor ordered him transferred to a hospital, according to the indictment.

The Israeli military said that it was committed to the rule of law and that investigators had collected “extensive” evidence to support the charges, including medical documentation and security camera footage.

In a statement, Mr. Amiram and Mr. Porat said they were certain that the charges against the soldiers would be dropped “when the facts are clarified in proceedings.”

The two charges made against the soldiers include jointly causing severe injury under aggravated circumstances and jointly abusing the detainee under aggravated circumstances.

Tal Steiner, the executive director of the Public Committee Against Torture in Israel, a human rights group, said the charges against the reservists were serious. She said while it was still too early to understand what kind of penalty they could face, Israeli military courts have acted relatively leniently in past cases in which Israeli soldiers were accused of using excessive force against Palestinians.

In 2017, Elor Azaria, a sergeant before he was demoted, was convicted of manslaughter and sentenced to 18 months in prison for killing Abdel Fattah al-Sharif, a Palestinian man in the Israeli-occupied West Bank. When Mr. Azaria shot Mr. al-Sharif dead, Mr. al-Sharif was already lying on the ground wounded; Mr. al-Sharif had been shot after stabbing another Israeli soldier. Mr. Azaria served nine months in prison and was later granted parole.

The case against the soldiers at Sde Teiman led to unrest last July, after videos surfaced of Israeli military police raiding the base to detain soldiers on suspicion of abusing the Palestinian.

Dozens of protesters gathered outside the base in solidarity with the soldiers, including at least three far-right lawmakers from Prime Minister Benjamin Netanyahu’s governing coalition. Hundreds later massed outside Beit Lid, a second base in which the soldiers had been brought for interrogation. Dozens surged inside both bases, brushing aside the guards at the gates.

At the time, Israeli military officials emphasized that no one was above the law, while right-wing protesters argued soldiers shouldn’t be punished for mistreating Palestinians accused of partaking in terrorist activities.

Many Palestinians who have been held at Sde Teiman have accused Israeli soldiers of carrying out grave acts of abuse against them. An investigation by The New York Times published last June found that by late May, roughly 4,000 Gazan detainees had spent up to three months in limbo at Sde Teiman. At least 1,200 people had been found to be civilians and returned to Gaza, without charge, apology or compensation.

The investigation found that those 1,200 Palestinian civilians had been held at Sde Teiman in demeaning conditions without the ability to plead their cases to a judge for up to 75 days. Eight former detainees, all of whom the military confirmed were held at the site and who spoke on the record, variously said they had been punched, kicked and beaten with batons, rifle butts and a hand-held metal detector while in custody.

Back then, the Israeli military denied that “systematic abuse” had taken place at Sde Teiman. When presented with individual allegations of abuse, the military said the claims were “evidently inaccurate or completely unfounded,” and might have been invented under pressure from Hamas. It did not give further details.

Gabby Sobelman contributed reporting to this article.

Thousands of tourists have stormed the snowy slopes of Sicily’s Mount Etna in recent weeks, congesting roads and obstructing the paths of rescue crews, the Italian authorities said, despite their efforts to keep people safely away from explosive lava flows.

Mount Etna regularly erupts, and it has drawn tourists for decades. But the latest eruption, which began on Feb. 8, has drawn so many photographers, hikers and nature aficionados that it has raised a chorus of warnings and orders from local Italian officials.

Salvo Cocina, Sicily’s regional civil protection leader, in a statement Sunday described a “constant flow” of about 1,000 people, as well as “wild parking on the edges of tight streets” that created an impasse for emergency vehicles.

“With the dark, the risk of falling and sinking into the snow increases proportionally with the increase of people,” he said.

“Etna is giving us a breathtaking spectacle: A lava flow has reached our territory,” Mayor Fabio Mancuso of Adrano warned his town near the foot of Etna a day earlier. “A lot of people are trying to get closer to admire this natural phenomenon, but it is extremely dangerous!”

He said the lava colliding with snow could cause violent explosions when the snow melts rapidly, resulting in high-pressure steam that can hurl rocks and lava a great distance. “A mortal danger for anybody near the flow!” he said in a social media post. “For this reason I have signed an order forbidding anyone from approaching the lava front.”

In Ragalna, another community on Etna’s slopes, the authorities ordered everyone to stay at least 500 meters, or nearly 550 yards, away from the lava flow.

But as the authorities issued orders, people still appeared to be uploading images and videos taken from the vicinity of the lava flows. Videos shared by the company AccuWeather showed people skiing down a snowy slope while lava smoldered and molten chunks of material tumbled down in the distance. In one clip, the silhouette of a sightseer’s body can be seen against red lava cascading not far in the background.

“Some people have independently managed to approach certain areas, but local municipalities have now imposed restrictions to prevent access to sites affected by the eruption for safety reasons,” said Giulia Campisi, a spokeswoman for a volcano tour agency, Go-Etna.

Ms. Campisi said in an email that the eruption was affecting Etna’s western flank, where fewer tourists know the trails. “To reach the lava flow in this particularly cold winter,” she said, “you must walk for a long time in deep snow.”

Go-Etna has not been taking tourists directly to the lava flows, she said, adding that it was abiding by local restrictions and safety measures. She also cited the danger that occurs when hot lava meets frigid snow.

“In some deeper spots, this can cause an immediate (and literally EXPLOSIVE) evaporation of the snow, resulting in the projection of hot stones, like bullets everywhere,” she said. “Events like these can take even experts by surprise.”

Stefano Branca, the director of the National Institute of Geophysics and Volcanology, called the activity a “typical summit eruption.” He added, “Only people who come within a few meters from the lava flow can be in danger as the heat of the lavas can cause small hydromagmatic explosions caused by the rapid melting of the snow.”

Elisabetta Povoledo contributed reporting.

The Trump administration has moved more than 175 men from an immigration holding site in Texas to the U.S. military base at Guantánamo Bay. All have been described as Venezuelans who have been issued final deportation orders. But it is not known why these men in particular were sent there.

Waves of migrants, including thousands of Haitians and Cubans, have been housed at the base over the years. But it is better known as a prison for wartime detainees captured after the terrorist attacks on Sept. 11, 2001. Because of that legacy, Guantánamo Bay sometimes evokes the idea of indefinite detention without charge, a legal black hole with no way out.

Here are some of the things we have learned about the migrant mission so far.

Is Guantánamo ready for 30,000 migrants?

On Jan. 29, President Trump ordered the Defense and Homeland Security Departments to prepare the base to receive up to 30,000 migrants.

Satellite imagery shows that tents have been going up near a building that was used for migrant operations in the past.

As of Tuesday, the military said there were about 850 troops and civilians assigned to migrant operations, more than 700 of them in the U.S. military.

With support from the Coast Guard, the military has been guarding and managing the Venezuelans in two separate buildings: the 120-bed Migrant Operations Center near the tents and a 176-cell military prison on the other side of the base for men the Trump administration has profiled as potentially dangerous or more dangerous. As of Wednesday, there were about 175 held there, 127 of whom were considered “high-threat illegal aliens,” according to a Defense Department official, who was not authorized to discuss the operation and spoke on the condition of anonymity.

Until now, the Migrant Operations Center has been the exclusive domain of the Department of Homeland Security, which has hired contractors to run it. As of last week, the Immigration and Customs Enforcement division of D.H.S. had 10 officers on temporary assignment for the entire migrant mission and plans to send 50 “contract security personnel,” homeland security representatives told Congress.

To expand it to a capacity in the tens of thousands, the administration will need to add more personnel. A military blueprint for the migrant operation shows plans to house more than 3,500 U.S. forces near tent encampments for more than 11,000 migrants.

The Trump administration has generally described the men sent to the base as including violent gang members being held for deportation, but has provided no proof.

The administration has not released their names or the specific basis for their planned deportation. But an examination of court records for some of the men, whose names are known, shows they entered the country illegally, for example by crossing the Rio Grande, and were picked up by border guards.

More recently, officials have been describing them as “illegal aliens.”

Are the Venezuelan men the next forever prisoners?

That may depend on whether the Trump administration can make arrangements for the Venezuelan government or another country to receive them.

U.S. officials have described the migrant mission at Guantánamo as a temporary holding site for people with final deportation orders. Complications could include whether individuals have claims to make that they should not be sent home, for example if they made asylum requests that were not fully adjudicated.

Even as Venezuelans arrive at Guantánamo, others have been sent back to Venezuela. On Feb. 10, Venezuela sent two planes to El Paso and picked up about 190 of its citizens, who were also under deportation orders. On the same day, a U.S. military cargo plane transported 15 men to Guantánamo Bay. Those men were put in the 120-bed dormitory.

As for Guantánamo’s terrorism-related detention mission, 780 Qaeda and Taliban prisoners were sent there from 2002 to 2008. Today, only 15 remain. They are held as military prisoners under the president’s war powers authority and are awaiting trial.

Could the migrants use the courtroom built for the Sept. 11 case?

Not without radically changing the law.

The law that created the military commissions system specifically limits its use to war crimes trials of foreign citizens who are members of Al Qaeda or their associates, specifically men held as detainees in the war against terrorism, an international armed conflict.

By U.S. law, the Qaeda prisoners at Guantánamo Bay cannot set foot on American soil.

The Venezuelans at Guantánamo are civilian, domestic prisoners who were taken into custody in the United States or at the southwest border, in a time of peace, and are technically in the custody of the Department of Homeland Security. They, like the war prisoners, may be able to challenge their detention in federal court.

But the migrants have not been accused of committing war crimes, and there is nothing prohibiting them from being flown back to the United States to appear in court.

What’s the big deal about U.S. troops guarding migrants at the terrorism prison?

For starters, there is concern about mission creep and the militarization of a civilian security challenge. There is also a question of whether it is legal, or a misappropriation of funds.

The U.S. military has traditionally provided security and support for the Department of Homeland Security in the United States but left the guarding and management of foreign citizens awaiting deportation to civilian immigration service employees and contractors. They operate under different rules, and often have the language skills and experience needed for the job.

At Guantánamo, the Army guards and Navy medics who work at the wartime prison and court were trained for a specific military police mission: housing and caring for long-held detainees from the war against terrorism. These are older men who have been at Guantánamo for 17 years or longer. Army prison guards and Navy medics are now caring for dozens of younger, Spanish-speaking men from immigration detention facilities that operate under different rules.

Also, some of the migrants are held in what could be called double military custody on the hard-to-reach base, whose access is controlled by its Navy commander.

Men who have been profiled as “high-threat illegal aliens” are held in a prison building that until recently held Qaeda suspects. That building is inside a special security zone for wartime detention operations, whose access is controlled by an Army colonel who answers to the U.S. Southern Command.

Do we know how much this will cost?

No, but it is going to be expensive. The tents and cots were already in storage at Guantánamo, in case of a humanitarian crisis in the Caribbean. But most of the provisions, including pallets of drinking water, will have to be airlifted to the base.

Prison and court functions for the war on terrorism operation have cost billions of dollars since 2002. That worked out to $13 million per prisoner per year, according to a 2019 study, including court costs.

But that operation has more fixed costs, with troops arriving on scheduled rotations on charter aircraft and housed in a barrack built for the prison guards.

Now the Pentagon has stepped up air missions to the base using C-17s and other costly Air Force cargo planes, and will need to mobilize, house and train more forces for the new mission.

Is this all part of a messaging strategy?

Certainly, the photos of men in shackles being loaded up on cargo planes to Guantánamo Bay may be sending messages.

Foreigners may be dissuaded from crossing illegally into the United States for fear of ending up at Guantánamo. Trump supporters may also see the operation as delivering on a promise the president made in his first campaign to load up the cells at Guantánamo with “bad dudes.”

Legal challenges have begun.

President Emmanuel Macron of France called a second emergency meeting of European allies on Wednesday seeking to recalibrate relations with the United States as President Trump upends international politics by rapidly changing American alliances.

Mr. Macron had already assembled a dozen European leaders in Paris on Monday after Mr. Trump and his new team angered and confused America’s traditional allies by suggesting that the United States would rapidly retreat from its security role in Europe and planned to proceed with peace talks with Russia — without Europe or Ukraine at the table.

Mr. Trump’s remarks late on Tuesday, when he sided fully with Russia’s narrative blaming Ukraine for the war, have now fortified the impression that the United States is prepared to abandon its role as a European ally and switch sides to embrace President Vladimir V. Putin of Russia.

It was a complete reversal of historical alliances that left many in Europe stunned and fearful.

“What’s happening is very bad. It’s a reversal of the state of the world since 1945,” Jean- Yves Le Drian, a former French foreign minister, said on French radio Wednesday morning.

“It’s our security he’s putting at risk,” he said, referring to Mr. Trump. “We must wake up.”

Fear that Mr. Trump is ready to abandon Ukraine and has accepted Russian talking points has been particularly acute in Eastern and Central Europe, where memories are long and bitter of the West’s efforts to appease Hitler in Munich in 1938 and its assent to Stalin’s demands at the Yalta Conference in 1945 for a Europe cleaved in two.

“Even Poland’s betrayal in Yalta lasted longer than Ukraine’s betrayal in Riyadh,” Jaroslaw Walesa, a Polish lawmaker and the son of Poland’s anti-Communist Solidarity trade union leader, Lech Walesa, said Wednesday on social media, referring to the American-Russian talks in Saudi Arabia on Tuesday.

Rasa Jukneviciene, a former Lithuania defense minister who is now a member of the European Parliament, said it was “hard to understand” the sudden shifts in policy by the United States, the once reliable pillar of Europe’s security for decades. She said she was “wondering what historians will write about the events of this time, say, in five decades.”

“It is already clear that the Euro-Atlantic connection will not be the same as it used to be,” she said. “The stage when European security after World War II was basically guaranteed only by the U.S.A. is over.”

Europe, she added, “is once again facing existential challenges” — akin to those in 1938 after Prime Minister Neville Chamberlain of Britain met Hitler in Munich and agreed to his annexation of parts of Czechoslovakia with a large ethnic German population.

In the power vacuum, Mr. Macron has tried to show leadership, corralling allied leaders to devise a united response.

The Élysée Palace announced that he would host a second emergency meeting on Wednesday of many European leaders who had not been included in the meeting on Monday. Among them were the interim president of Romania, Ilie Bolojan, and Prime Minister Luc Frieden of Luxembourg, who would attend in person, while leaders from 18 other countries were scheduled to attend by video. They included Ireland, Iceland, Portugal, Sweden, Finland, Norway, the Czech Republic, Estonia, Latvia, Greece, Sweden and Belgium.

The meeting comes the day after Secretary of State Marco Rubio met with Russian representatives, including Foreign Minister Sergey V. Lavrov, in Riyadh, Saudi Arabia, to discuss a peace deal for the war in Ukraine, to the fury of its president, Volodymyr Zelensky, who was not invited.

Mr. Rubio said they hammered out a three-part plan, which would start by re-establishing bilateral relations between Washington and Moscow and end by exploring new partnerships — geopolitical and business — between Russia and the United States, while addressing the parameters of an end of the war with Ukraine in between.

Mr. Rubio said he would consult with Ukraine, the American “partners in Europe and others,” but in the end, “ultimately, the Russian side will be indispensable to this effort.”

Afterward, speaking to reporters at his Mar-a-Lago estate in Florida, Mr. Trump blamed Ukraine for starting the war, despite the fact that Russia had invaded.

“You could have made a deal,” he said, denigrating Mr. Zelensky’s popularity and indicating he didn’t deserve a seat at the negotiating table.

“Well, they’ve had a seat for three years. And a long time before that,” Mr. Trump said. “This could have been settled very easily. Just a half-baked negotiator could have settled this years ago without, I think, without the loss of much land, very little land. Without the loss of any lives. And without the loss of cities that are just laying on their sides.”

Mr. Trump’s comments blaming Ukraine for the war stirred outrage in the Czech Republic, whose centrist government has been a stalwart supporter of Ukraine. “I’m afraid we’ve never been this close to Orwell’s ‘war is peace, freedom is slavery, and ignorance is strength’ before,” Interior Minister Vit Rakusan said on social media.

Mr. Le Drian called it a monstrous reversal of world alliances, as well as an “inversion of the truth.”

“The victim becomes the attacker,” he said, adding that the United States seemed to be retreating to a 19th-century view of itself, and telling an aggressive, expansionist Russia to do what it wants in Europe. “It’s the law of the strongest,” he said, adding, “Tomorrow, it could be Moldavia and after tomorrow, it could be Estonia because Putin won’t stop.”

Marko Mihkelson, chairman of the Estonian Parliament’s foreign affairs committee, also compared the Riyadh meeting with the 1938 talks in Munich. “All of this paves the way for the aggressor to achieve its new plans of conquest,” he said.

Before Mr. Rubio and Mr. Trump’s pronouncements on Tuesday, Mr. Macron said he considered the Russian threat to Europe not just in military terms, but through slyer means, including cyberattacks and manipulation of electoral processes like Romania.

“Russia constitutes an existential threat to Europeans,” Mr. Macron said on Tuesday in an interview with French regional newspapers, including Le Parisien and Ouest France.

“Do not think that the unthinkable cannot happen, including the worst,” he added.

On Monday, a dozen European leaders left a quickly organized meeting in Paris with a resounding message that Europeans and Ukrainians needed to be included in any peace talks with Russia and a commitment to increase military funding.

Many made clear that they wanted a continued alliance with the United States, which they considered indispensable to European security.

“The positive message was that we all had the same feeling that this is not about the U.S. or Europe, but it’s about the U.S. and Europe together, and that Europe understands very well that we have to step up, but that we want to still do it together with the Americans,” Prime Minister Dick Schoof of the Netherlands said.

Mr. Trump’s latest statement poured water on many of those sentiments and may now force a deeper reconsideration of the trans-Atlantic alliance by European leaders.

Mr. Macron has been speaking for months to European leaders about forming a cease-fire buffer force in Ukraine and has long called for European strategic autonomy. Still, he told the French regional news media that he did not believe European countries could defend themselves without American support.

He said that he expected European countries to increase their military budgets and would announce new programs to allow them to do that “as early as March.” Denmark said on Wednesday that it would increase its $5 billion military budget by an additional $7 billion over two years, to reach 3 percent of gross domestic product.

Already, the European Commission president, Ursula von der Leyen, announced in a speech that she would propose an “escape clause for defense investments” permitting countries to fund defense without breaching the European Union’s strict fiscal rules, which aim to keep budget deficits under 3 percent of the size of each country’s economy.

“This will allow member states to substantially increase their defense expenditure,” she said.

Europeans are also discussing joint spending on defense — including how to finance those, which could involve issuing joint debt, though that is still up for debate. They are also talking about how to ramp up the development of European defense industries.

Over the past week, Europe’s steadfast position that held the United States as the central pole of its defense guarantee seems to be changing, said Martin Quencez, the director of the Paris office of the German Marshall Fund.

The big question will be whether European nations follow through with increased military spending and maintain a united front, without fracturing off to individually negotiate with Mr. Trump, he said.

“I’ve heard Europe talk about wake-up calls so many times over the past 10 years, I remain cautious,” he said, pointing out that many European leaders, including Mr. Macron, find themselves in fragile political and economic positions in their own countries.

“I’m sure we will hear from every European leader, but let’s see what actual decisions are taken,” he said, adding: “It’s very, very difficult to tell your population, we’re going to have to make the tough choice of prioritizing European security over social issues or environmental issues. Not many governments have the political capital to spend on all this.”

Poland, the biggest and most militarily powerful country in the European Union’s formerly communist east, sought on Tuesday evening after the talks in Saudi Arabia ended to calm the panic.

That day, President Andrzej Duda was visited in Warsaw by Mr. Trump’s special envoy for Ukraine and Russia, Keith Kellogg, a retired lieutenant general. The Polish leader said Mr. Kellogg reassured him that “there are absolutely no American intentions to reduce activity here in our part of Europe, especially in the field of security, to reduce the number of American soldiers.”

The United States has thousands of soldiers in Poland and in November opened a new missile defense facility near the Baltic Sea that Russia sees as a threat to its own security. Getting Washington to shut down the Polish site and a similar one in Romania has been a longstanding demand by Mr. Putin.

Jeanna Smialek contributed reporting from Brussels.