Two days before last Christmas, Dr. Pierre S. Prince took an exciting new job as director of Haiti’s largest public hospital, which the United States spent tens of millions of dollars renovating and is so deep in gang territory that it has been closed for a year.

Dr. Prince, a 57-year-old thoracic surgeon, looked forward to returning to the State University Hospital of Haiti, which had been ravaged by the 2010 earthquake that decimated the country’s capital.

He did his residency there and was going to oversee a new wing, a 500-bed facility with nearly $100 million in renovations and a range of services, including operating rooms, orthopedics and a maternity and neonatal unit.

On Christmas Eve, as he headed to work, gangs attacked a news conference scheduled to announce the hospital’s partial reopening, killing a police officer and two reporters, and seriously injuring seven other journalists. The reopening never happened.

The situation worsened last month: Videos that circulated on social media and were verified by The New York Times showed an older building at the general hospital, as it is commonly known, engulfed in flames. Gang members had apparently set it on fire.

“The doctors are scared, and our residents and interns are depressed,” Dr. Prince said. “Some of them have left. The morale is very low.”

The hospital’s fate underscores the increasingly desperate conditions facing Haiti and its international donors as they try to rescue Port-au-Prince from the control of armed gangs, which have targeted foreign-financed health facilities.

Haiti, where the United Nations says about 20 percent of its 10 million people is enduring acute levels of hunger and 1 million have fled their homes because of violence, is particularly dependent on foreign aid and had been receiving up to $400 million a year from the United States alone.

But as Elon Musk takes an ax to American foreign aid around the world, and dismantles the U.S. Agency for International Development, programs like the continued renovation of the general hospital in Port-au-Prince are in the cross hairs.

The hospital’s new wing, which U.S. A.I.D. helped pay for, was already plagued by large cost overruns and a decade of construction delays. Now it is being battered by repeated assaults from criminal groups as Haiti’s capital has become a lawless quagmire despite billions of dollars in international aid.

“The general hospital is sort of like a case study on how it goes wrong,” said Jake Johnston, a researcher at the Center for Economic and Policy and Research who wrote “Aid State,” a blistering account of how billions in international aid failed to bolster Haiti’s public institutions. “And they never finished the work, and the general hospital is closed for all these other reasons.”

Haiti’s general hospital was built next to the presidential palace in downtown Port-au-Prince by the U.S. Army Corps of Engineers during the American occupation of Haiti, from 1915 to 1934.

For years, many patients were gunshot and torture victims. In a country where politicians and wealthy elites travel to the Dominican Republic or Miami for health care, the general hospital served the overwhelmingly poor masses.

“It housed the only dialysis machines in the country,” said David Ellis, an American who runs a medical helicopter service in Port-au-Prince. “It was, when open, the most comprehensive surgical center in the country.”

It was so badly damaged in the 2010 earthquake that no one was able to treat the hundreds of severely injured people gathered outside, their bloody mangled limbs exposed to the dusty air.

Renovating the hospital was one of the first projects approved by an international reconstruction committee formed to rebuild Haiti after the earthquake. France committed $40 million, the United States $25 million.

After a series of delays and contract disputes, it was slated for completion in June 2023 — nine years later than originally planned.

At the same time, the political situation in Haiti deteriorated precipitously. The president was assassinated in 2021, and kidnappings and killings soared.

In July 2022, U.S. A.I.D. increased its contribution by $10 million because the Haitian government could not pay its share, according to a 2023 report by the Government Accountability Office, a congressional watchdog agency.

The hospital was just one of several projects the G.A.O. examined that ended up over budget. The United States spent $2.3 billion to support Haiti’s reconstruction in the decade after the quake, and only half of the eight major projects G.A.O. reviewed were completed.

While a key power plant and roughly 900 homes were built in Port-au-Prince, two projects, including building a new port, were scrapped when costs soared and two others — including the general hospital — were still ongoing.

Technical and political disputes caused significant delays and cost overruns at the hospital, the G.A.O. said.

But the hospital limped along, half-open, while work on the new wing stalled.

Then a year ago, a coalition of gangs banded together to attack police stations, prisons, hospitals and communities. Gangs set homes on fire, and entire neighborhoods — including the downtown area that is home to the hospital — cleared out.

The former prime minister had to dodge gunfire during an official visit to the general hospital last year and was whisked away by his security detail while CNN cameras rolled.

With the area too perilous, the more than 800 people who work at the hospital, including doctors and nurses, have been paid to stay home for nearly a year.

“It seems that there is an intense desire to make us waste time,” said Dr. Stevens Gabriel, a resident surgeon who complained of not being reassigned to another facility to continue advancing his skills and training.

Even though police barracks are nearby, gangs plundered the general hospital. The governments of the United States, France and Haiti had already spent about $90 million on it. Electrical wiring, plumbing and equipment were stolen, though much of the new medical equipment had not yet been installed, Dr. Prince said.

The damage was estimated at $3 million to $4 million and could set the project back another two years — if the security situation ever improves enough for the hospital to reopen, he said. Now Dr. Prince says they are scouting for a new temporary place to work.

Eleonore Caroit, the French member of Parliament for citizens living overseas in Latin America and the Caribbean, who sits on the board of the development agency that helped finance the project, said drone footage was being used to assess damage from the recent fire.

“France is willing to do what it can to help,’’ she said, “but the situation is very complicated. My constituents tell me it’s never been this bad.”

Satellite imagery captured eight days after the fire by the commercial satellite company Planet Labs shows one older building charred and at least two others damaged.

Dr. Barth Green, the chairman of Project Medishare for Haiti, a Miami-based charity and a major supporter of health services in the country, said the attack was particularly dispiriting because the general hospital was where generations of nurses and doctors trained.

“That’s the national university hospital,” he said, “And so, by destroying this, it’s a symbol.”

The issue is critical: Only one of three major hospitals in the capital area is open. Of the 92 health facilities in the metropolitan area, only 39 are operational, according to the Pan American Health Organization.

Under the Trump administration’s new push to eradicate foreign aid, funds for most projects financed by U.S.A.I.D. were frozen, although a judge recently ruled that the agency had to fulfill past contracts.

Asked about the hospital’s status, the U.S. State Department, which has assumed control of the aid agency, said it would conduct a review with the goal of “restructuring assistance to serve U.S. interests.”

“Programs that serve our nation’s interests will continue,” the State Department said in a statement. “However, programs that aren’t aligned with our national interest will not.”

The Haitian Ministry of Health did not respond to requests for comment.

Responding to a post on X criticizing the billions spent in Haiti after the earthquake, Prime Minister Alix Didier Fils-Aimé agreed that much of the American assistance had been squandered.

“You’re right!!” he wrote in a message directed at Mr. Musk, “USAID spent billion (sic) on Haiti with no accountability. Haiti needs economic development and security, not corruption and cronyism.”

He added that he looked forward to working with President Trump to achieve economic prosperity for Haiti.

Devon Lum contributed reporting. Dmitriy Khavin contributed video editing.

Germany’s next chancellor, Friedrich Merz, set European pigeons flying in circles when he suggested last month that given rising mistrust in President Trump’s commitment to NATO, he wanted to talk to France and Britain about extending nuclear deterrence over Germany.

Warning that a “profound change of American geopolitics” had put Poland, as well as Ukraine, in an “objectively more difficult situation,” Prime Minister Donald Tusk of Poland suggested the same, while hinting that Poland, with its long history of Russian occupation, might eventually develop its own bomb.

Then Poland’s president, Andrzej Duda, said this week that it was time for the United States to consider redeploying some of its nuclear weapons from Western Europe to Poland. “I think it’s not only that the time has come, but that it would be safer if those weapons were already here,” Mr. Duda told the Financial Times.

The uproar was immediate, given the sensitivity and complications of the nuclear issue and the whole concept of extended deterrence — the willingness of a nuclear-armed country to use its nuclear weapons in defense of a nonnuclear ally. That commitment is at the heart of NATO’s Article Five, promising collective defense, and hinges on the massive American nuclear arsenal.

Mr. Trump and his officials say they remain committed to extending the American nuclear umbrella over Europe, the vital deterrent to any serious Russian aggression, and to the alliance itself. But his evident hostility toward Europe has so unnerved America’s traditional European allies that it has provoked strong doubts that they can depend on the United States.

There are fears that talking too much about a European replacement, let alone trying to construct one, would only encourage Mr. Trump to withdraw his pledge. Even so, European allies are now engaged in the most serious debate in generations about what Europe’s nuclear defense should be.

Like many things when it comes to European defense, replacing the American commitment would not be easy.

Today France and Britain are the only two Western powers in Europe who possess nuclear weapons. For others, like Germany, to join the nuclear club would be expensive, require leaving the Nuclear Nonproliferation Treaty and could seem more threatening to Moscow, raising risks rather than lowering them.

But together, the French and British have only about 500 warheads compared with some 3,700 in the American arsenal, with another 1,300 or so waiting to be deactivated. The Americans also have what is known as the “triad” — nuclear weapons on land-based missiles, bombers and submarines.

The French have no land-based missiles but do have nuclear-equipped bombers and submarines, while the British have only submarines.

And only the French nuclear arsenal is truly independent of the United States, technically and politically. France has always refused to join NATO’s nuclear planning group, keeping sole authority on the use of its weapons in the hands of the French president, currently Emmanuel Macron.

The British deterrent depends on American Trident II missiles, launching mechanisms and maintenance, raising at least the question of whether the British government has full authority to launch these weapons.

French doctrine has always been kept a bit vague, part of the uncertainty that is the heart of deterrence. “We have a pretty good idea what the French will not do, but not such a clear understanding of what they are willing to do,” said Claudia Major, head of trans-Atlantic security studies for the German Marshall Fund.

Since 2020, Mr. Macron has sometimes spoken of France’s vital national interests as having “a European dimension,” without specifying what that is. Earlier this month, he announced a “strategic debate on using our deterrence to protect our allies on the European continent.”

“But how far does that ‘European dimension’ go?” Ms. Major asked. “The French won’t define it and of course don’t want Russia to know.”

The security of neighboring Germany and perhaps Poland would likely qualify as vital French national interests, said Erik Jones, director of the Robert Schuman Center at the European University Institute.

But it is far from clear that a quick conventional Russian attack on Estonia or Lithuania would prompt a French nuclear threat or response. “The vital interests of France do not reach that far,” he said.

The French nuclear deterrent is not meant to provide an American-style extended deterrence on the cheap, said Camille Grand, a former French and NATO defense official. But it does provide another degree of uncertainty for Moscow that complements and even strengthens NATO nuclear policy, he said.

Since both France and Britain are European, their national interests are more likely to stretch to the European neighborhood than is the case for the distant United States, Mr. Grand argued.

Then there is the question of the next French president. Should it be Marine Le Pen, the head of the far-right National Rally, she might have a narrower view of French interests. That could undermine the credibility of an extended French nuclear deterrent in the same way that Europeans have become anxious over Mr. Trump’s commitment.

Still, with both bombers and submarines, France maintains an “escalation ladder,” with the ability to threaten use without doing so. For example, in February 2022, after the Russian invasion of Ukraine, France put a third nuclear submarine out to sea, “a quiet but explicit message that the Russians saw,” Mr. Grand said.

As Mr. Merz and the Polish leaders suggested, France might also consider “nuclear sharing,” as the Americans now do. There are five European countries — Germany, Italy, Belgium, the Netherlands and Turkey — that currently host American B61 nuclear bombs and have their own airplanes to deliver them.

Poland would like to be a sixth. While French nuclear-capable bombers have been refueled by Italy, for instance, for France to decide to place some of its nuclear weapons and bombers in other countries would be a break with its current doctrine. In any case, France and its president would retain total control over their use.

Submarines by themselves do not provide an escalation ladder, because they are supposed to remain hidden, and either fire missiles or don’t. That is one reason British officials are considering restoring the air leg of their deterrent. Ideally, the British would also benefit from another nuclear-capable submarine, so more than one can be at sea. But the expense is enormous.

And there is no way to share a submarine with another country, the way an air-launched bomb or missile can be shared.

In the end, the core of NATO’s nuclear deterrent remains the United States, said Ivo Daalder, a former U.S. ambassador to NATO.

The question for him is less the number of warheads than the credibility of the deterrence. “How to make a deterrent versus Russia credible when you’re an ocean away and convince allies you’re willing to make the ultimate sacrifice for them?” he asked. “Unfortunately, Trump answers those questions without even raising them.”

Given all the uncertainty, Germany might have to go nuclear itself, said Thorsten Benner, director of the Global Public Policy Institute. “So far talk of a German bomb has been limited to fringe types, but now it becomes more mainstream,” he said. But he prefers discussing nuclear sharing with France, with French bombers on German bases.

Matthew Kroenig, a former defense department official who directs the Scowcroft Center for Strategy and Security at the Atlantic Council, thinks the debate has been beneficial to get Europeans to take defense more seriously.

“NATO allies should do a lot more of the nuts and bolts of conventional defense, but some high-end stuff like nuclear deterrence — only the United States can provide,” he said.

Ms. Major has another concern, widely shared. “The more we do for defense the better for us,” she said. “But does it send the wrong signal and have the unintended consequence of America leaving? It’s the decoupling argument that we fear so much.”

Israeli forces killed at least nine Palestinians in Gaza in strikes on Saturday, according to the Gaza health ministry, the latest in a string of Israeli attacks on the enclave that have kept up despite a roughly two-month-old truce with Hamas.

Since the cease-fire went into effect in mid-January, the military has conducted constant strikes in Gaza. Israel has accused militants of threatening its forces by laying explosive devices, flying drones or by approaching where Israeli troops are deployed.

Hamas has claimed those attacks have killed more than 150 people since the truce took effect, at least some of them civilians. And it has accused Israel of repeatedly violating the agreement by continuing military operations.

On Saturday, the Israeli military said it struck two militants who were operating a drone that posed a threat, and then struck a vehicle carrying others who had arrived to collect the drone operating equipment. It did not elaborate on how they posed a threat to Israeli troops.

Ismail Thawabteh, the director-general of the Hamas-controlled government media office in Gaza, said the nine Palestinians killed in the strike were working for a charity. The identities and statuses of those killed could not be independently verified.

The Israeli military said earlier on Saturday that it had struck three militants in central Gaza who were attempting to install explosive devices on the ground near Israeli soldiers. Officials in the Gaza health ministry did not respond to requests for comment.

The steady drumbeat of Israeli strikes is a reminder that while Israel and Hamas have reached an agreement that paused most fighting in Gaza, a comprehensive truce is still nowhere in sight. In Lebanon, Israel is conducting a similar aerial campaign against the Lebanese armed group Hezbollah — a Hamas ally — during the U.S.-brokered cease-fire there, saying Israeli forces are attacking sites and operatives that have breached the agreement.

The war in Gaza began after Hamas’s deadly Oct. 7, 2023 attack on southern Israel, which killed about 1,200 people, mostly civilians, according to Israel’s government. About 250 others were taken back to Gaza as hostages.

Israel’s subsequent military campaign against Hamas has killed more than 48,000 people, including thousands of children, according to the Gaza health ministry. The figures do not distinguish between civilians and combatants and the Israeli military claims to have “eliminated” nearly 20,000 Hamas operatives.

Israeli leaders say they will not end the war against Hamas until they topple the group’s rule in Gaza and the territory no longer poses a threat to Israel. Hamas has shown some willingness to give up civilian governance of Gaza, but has drawn a red line on disbanding its battalions of armed fighters.

Israel and Hamas are supposed to be negotiating the next steps in the cease-fire agreement, which would involve a permanent end to the war, the release of the remaining living hostages, and a full withdrawal of Israeli forces from Gaza.

Mediators including the United States, Qatar, and Egypt have made little headway so far given the entrenched disagreements between the two sides.

Israeli forces remain deployed in a buffer zone inside Gaza and along the Philadelphi Corridor, which runs along Gaza’s border with Egypt. Under the terms of the cease-fire, Israel was supposed to have withdrawn from the Philadelphi Corridor by mid-March.

Iyad Abuheweilaand Lia Lapidotcontributed reporting.

Moscow is pressing its offensive to retake the full territory of Russia’s Kursk region from Ukraine as negotiations between the White House and the Kremlin continue over a possible cease-fire in the three-year war.

Russia’s Defense Ministry said on Saturday that its forces had retaken two villages outside Sudzha, the main Russian town that Ukraine occupied since its surprise offensive into Russia last summer but appears to have lost in recent days. Ukrainian officials did not immediately comment on Russia’s newest claim and have not confirmed a retreat by its forces from Sudzha.

Moscow’s advances on the Kursk front came a day after President Vladimir V. Putin of Russia called on Ukrainian forces still fighting in the region to lay down their arms. Mr. Putin said he would spare their lives if they surrendered.

The Kremlin spokesman, Dmitri S. Peskov, reiterated Mr. Putin’s demand in comments to the state news agency Tass on Saturday.

“It’s still valid,” Mr. Peskov said, although he added that “time was running out.”

The Russian leader has said that Ukrainian forces are encircled in the region, an assertion that President Trump repeated in a message on Truth Social.

But President Volodymyr Zelensky of Ukraine denied that the Ukrainian troops were surrounded.

“Our troops continue to hold back Russian and North Korean groupings in the Kursk region,” Mr. Zelensky said in a post Saturday on Facebook, referring to North Korean fighters who have been assisting Russia in Kursk. “There is no encirclement of our troops.”

Mr. Zelensky said Russia was not only pressing an offensive in the Kursk region, but also planning a new assault on the neighboring Sumy region of Ukraine.

“We are aware of this and will counter it,” Mr. Zelensky said. “I would like all partners to understand exactly what Putin is planning, what he is preparing for and what he will be ignoring.”

Mr. Putin said last year that Russia would not hold any negotiations with Ukraine so long as Ukrainian troops were still in Russia’s Kursk region. He has also talked about a need for “buffer zones” in Ukraine’s border regions to prevent attacks on Russian soil.

On Thursday, he appeared in no hurry to accept the offer of a 30-day truce made by Ukraine and the United States — telling a news conference that he was open to the proposal but that he would seek to negotiate over issues like Western weapons deliveries to Ukraine.

As the battlefield in Kursk shifted, Prime Minister Keir Starmer of Britain was convening a virtual summit on Saturday of global leaders committed to aiding Ukraine. “We can’t allow President Putin to play games with President Trump’s deal,” Mr. Starmer said in a statement as he prepared to host the meeting.

“The Kremlin’s complete disregard for President Trump’s cease-fire proposal only serves to demonstrate that Putin is not serious about peace,” the British leader said.

While Ukraine reeled from a temporary cutoff of U.S. military aid and intelligence assistance last week, Moscow stepped up its efforts to retake Kursk. In recent days, Russian forces have been escalating attacks in the area and in the Sumy region.

The Russian attacks there have included attempts to enter Ukrainian territory using small sabotage groups and increased shelling of the border and the regional capital, the city of Sumy, according to Ukrainian officials. A total of 161 explosions were reported in the Ukrainian region over the last night, officials said.

Shahed drones also targeted critical infrastructure in Sumy, leading to power outages and disruptions to the water supply, they said.

The operations in Kursk and Sumy come as part of a broader jump in attacks.

Overnight, Russia launched two Iskander-M ballistic missiles and 178 drones at Ukrainian cities, the Ukrainian authorities said. The missiles struck a residential district in Kryvyi Rih, Mr. Zelensky’s hometown in central Ukraine, injuring 14 people, including two children, according to the local authorities

Small assault groups from Russia entered the northern border region of Ukraine on Friday but were pushed out, Andriy Demchenko, the spokesman for the State Border Guard Service of Ukraine, said in a phone interview.

“Their task is to break through and wedge their way in, but so far they haven’t succeeded,” Mr. Demchenko said.

He said that Russian forces had tried to use armored vehicles and three all-terrain vehicles to break through the border but had been unsuccessful. In their latest attempt, soldiers tried to enter Ukrainian territory on foot in small groups of up to five soldiers, he said.

Russia’s Defense Ministry also said that Russian engineering forces had begun demining areas that its forces had retaken in the Kursk region near the border with Ukraine.