The man widely called the true winner of Venezuela’s tainted presidential election said on Tuesday that his son-in-law had been kidnapped by hooded men in Caracas, the capital.

Edmundo González said that his son-in-law, Rafael Tudares, was walking Mr. González’s grandchildren to school when he was “intercepted” by hooded men dressed in black, and taken away in a gold van.

“At this time he is missing,” he wrote on X.

The reported kidnapping comes one day after Mr. González met at the White House with President Biden, whose administration recognizes Mr. González as president-elect, in an effort to put international pressure on President Nicolás Maduro, the longtime authoritarian leader who claims he won Venezuela’s July election.

On Monday the Maduro government, in a statement, called the meeting “a flagrant violation of international law and a crude attempt to perpetuate imperialist interference in Latin America.”

Mr. González, 75, was forced to flee the country shortly after millions of Venezuelans voted for him, and he is now living in exile in Spain. He has promised repeatedly to return to his country to be sworn in on Friday, when Maduro, in power since 2013, is scheduled to be inaugurated for another six-year term.

The Maduro government has imposed a $100,000 bounty on Mr. González and he likely faces arrest if he returns.

The Venezuelan government has unleashed a wave of repression against anyone who challenges its declared victory, arresting about 2,000 people and charging most with terrorism. Human rights groups have described it as Venezuela’s most brutal campaign of repression in recent decades.

The government has released hundreds of those prisoners in recent months, in what many analysts saw as a signal to President-elect Donald J. Trump that it is willing to ease up on human rights in exchange for favorable treatment.

Ireland has formally joined South Africa’s genocide case against Israel, according to a statement on Tuesday from the International Court of Justice.

The filing, made on Monday, comes months after Ireland announced plans to intervene in the case before the United Nations’ highest judicial body.

“Ireland, invoking Article 63 of the Statute of the Court, filed in the Registry of the Court a declaration of intervention in the case concerning Application of the Convention on the Prevention and Punishment of the Crime of Genocide in the Gaza Strip,” the court said in a statement on Tuesday.

South Africa brought its case to the I.C.J. in December 2023, accusing Israel of committing genocide in Gaza. Israel has strongly rejected the allegation, describing South Africa’s filing as a “despicable and contemptuous exploitation of the Court.”

In an initial ruling in January 2024, the court ordered Israel to restrain its attacks in Gaza, and in May it ordered the country to immediately halt its military offensive in the city of Rafah, in southern Gaza.

The United Nations allows countries to “intervene” in proceedings if they are parties to the United Nations’ 1948 Genocide Convention.

The Irish government did not immediately respond to a request for comment on Tuesday, but the filing was long anticipated. Last month, the government approved a plan to file its argument in the case, with Micheál Martin, the deputy prime minister and minister for foreign affairs, saying that it would be filed in The Hague, where the court is based, within weeks.

“There has been a collective punishment of the Palestinian people through the intent and impact of military actions of Israel in Gaza, leaving 44,000 dead and millions of civilians displaced,” Mr. Martin said in December, adding that Ireland would ask the court to broaden its interpretation of what constitutes the commission of genocide by a state.

“We are concerned that a very narrow interpretation of what constitutes genocide leads to a culture of impunity in which the protection of civilians is minimized,” he added.

Experts say the court is not expected to rule on the genocide charge for years.

The decision to intervene in the case reflects Ireland’s longstanding support for Palestinian civilians, rooted in part in a shared history of British colonialism and in Ireland’s own experience with a seemingly intractable sectarian conflict — The Troubles, which came to a close with the 1998 Good Friday Agreement.

Last month, Israel announced it was closing its embassy in Dublin, citing what it said were “the extreme anti-Israel policies of the Irish government.” Israeli officials said the action did not mean that Israel was severing diplomatic relations with Ireland.

President-elect Donald J. Trump said Tuesday that he would not rule out the use of military or economic coercion to force Panama to give up control of the canal America built more than a century ago and to force Denmark to sell Greenland to the United States.

In a rambling, hourlong news conference, Mr. Trump also reiterated his threat that “all hell will break out in the Middle East” if the hostages being held by Hamas are not released by Inauguration Day, repeating the threat four times.

“If they’re not back by the time I get into office, all hell will break out in the Middle East,” he told reporters. “And it will not be good for Hamas, and it will not be good, frankly, for anyone. All hell will break out. I don’t have to say anymore, but that’s what it is.”

Mr. Trump did not elaborate during the news conference, where he delivered a hodgepodge of grievances, complaints and false claims, from the Afghanistan withdrawal of 2021 to offshore drilling to the criminal cases against him and the size of his electoral victory.

He refused to rule out using military force to retake the Panama Canal, which was given back to Panama by treaty in the late 1990s, and Greenland, which Mr. Trump said was necessary for the national security of the United States.

“It might be that you’ll have to do something,” he said.

Trump’s desire to expand the U.S. footprint is entirely in keeping with his mind-set of making whatever he controls as big as possible, going back to his series of acquisitions in the late 1980s. In recent days, Mr. Trump has talked repeatedly about buying Greenland and taking over the Panama Canal.

It was not clear how serious the president-elect was about some of his comments during the news conference. At one point, he suggested that his administration will rename the Gulf of Mexico the Gulf of America.

The news conference was a back-to-the-future moment for Mr. Trump, who often used similar appearances as president to seize control of the public narrative with attacks on his adversaries and bombastic and often false assertions about his accomplishments.

In an appearance in front of reporters that had been described as an economic development announcement, Mr. Trump lashed out at President Biden for banning oil drilling in some waters, said the special counsel who investigated him is “deranged” and assailed the New York judge overseeing a criminal case against him.

“That’s a sick group of people, and it was all to influence the election,” Mr. Trump said. “It was all a fight against their political opponent. We’ve never had that in this country. We have had that in certain countries. We’ve had that in third tier countries.”

Before taking questions, Mr. Trump talked for more than a half-hour without focusing on any single topic. He ranted about Mr. Biden’s focus on electric cars, saying “I don’t know what it is with electric. This guy loves electric.” And he complained about shower heads with restricted water flow.

“It’s called rain, comes down from comes down from heaven. And they want to do, no water comes out of the shower,” he said. “It goes drip, drip, drip. So what happens you’re in the shower 10 times as long, you know. No water comes out of the faucet.”

He also returned to one of his favorite targets: his hatred of windmills.

“The windmills are driving the whales crazy,” he said.

The president-elect talked at length about foreign policy, criticizing Mr. Biden’s handling of the war in Ukraine, the Afghanistan pullout, and the conflict in Israel. He also repeated his threat not to protect NATO allies, a foundational part of the pact, if they did not increase the amount of money they spend on defense of their own countries.

At one point, he appeared to confirm a recent story in the Financial Times suggesting that he wants NATO countries to commit to spending up to 5 percent of their economic output on defense, a significant increase.

He also criticized Canada, saying that the country should be a state in the United States because of the economic support that the United States provides to the country. He said he would not use military power to achieve that but said that he would use economic power to pressure the American neighbor.

“Why are we supporting a country, 200 million plus a year?” he told reporters. “Our military is at their disposal all of these other things. They should be a state. That’s what I told Trudeau when he came down.”

Mr. Trump threatened to use “economic force” to join Canada and the United States together, implying that the United States would pare back its purchases of Canadian products.

He also said he would “tariff Denmark at a very high level” if it does not give Greenland to the United States.

During the news conference, Mr. Trump was told that a federal judge had blocked Jack Smith, the special counsel who had been investigating his actions on Jan. 6 and his handling of classified documents, from releasing a report about the investigations.

“So if they’re not allowed to issue the report, that’s the way it should be,” he said. “Why should he be allowed to write a fake report? It’ll only be a fake report. That’s great news.”

The United States declared on Tuesday that a genocide took place in Sudan, drawing fresh attention to the scale of atrocities in Africa’s largest war and singling out one side in the conflict as the perpetrators of some of the worst violence.

Secretary of State Antony J. Blinken said the Rapid Support Forces, a paramilitary group fighting Sudan’s military in a bitter civil war, and allied militias had committed acts of genocide during a fearsome wave of ethnically targeted violence in the western region of Darfur.

The Treasury Department announced a raft of financial measures intended to support the genocide determination, including sanctions that personally target the R.S.F.’s leader, Gen. Mohamed Hamdan, as well as seven companies in the United Arab Emirates, the R.S.F.’s main foreign sponsor.

“The R.S.F. and allied militias have systematically murdered men and boys — even infants — on an ethnic basis, and deliberately targeted women and girls from certain ethnic groups for rape and other forms of brutal sexual violence,” Mr. Blinken said in a statement. “Those same militias have targeted fleeing civilians, murdering innocent people escaping conflict, and prevented remaining civilians from accessing lifesaving supplies.”

The genocide determination comes two decades after the United States took a similar step in 2004, when then Secretary of State Colin Powell determined that the Janjaweed, ruthless ethnic militias allied with Sudan’s military, had committed genocide during a vicious counterinsurgency campaign in Darfur.

The Janjaweed later morphed into the Rapid Support Forces. But instead of being allied with Sudan’s military, the group is now fighting it, in a civil war that has driven one of Africa’s largest countries into a devastating famine, killed tens of thousands of people and forced more than 11 million people — almost one-quarter of Sudan’s population — to flee their homes, according to the United Nations.

Atrocities and war crimes have been committed on both sides, say officials from the United States, the United Nations and human rights groups. The military has repeatedly massacred civilians in indiscriminate bombing raids, sometimes killing dozens at once.

But only the R.S.F. has been accused of ethnic cleansing, particularly during a systematic wave of violence in Darfur between April 2023 — when the civil war began — and November of that year. The group targeted members of the Masalit ethnic group, a central element in the American genocide determination, said two senior U.S. officials who spoke on condition of anonymity to discuss sensitive diplomatic matters. (The Masalit are ethnic Africans and the R.S.F. are dominated by ethnic Arabs.)

The toll of that violence is unclear. The Sudanese Red Crescent said it counted 2,000 bodies in a single day, then stopped counting. U.N. investigators later estimated that as many as 15,000 people were killed in the city of Geneina alone.

More than three million people have fled Sudan for neighboring countries, the United Nations says, including hundreds of thousands of Masalit civilians who are living in squalid, overcrowded camps in Chad.

The genocide determination followed months of deliberation inside the U.S. government, as lawyers and intelligence officials evaluated the merits of the case, said the two senior U.S. officials. Some officials hesitated to support the determination because they feared it might draw further criticism of the Biden administration over its refusal to declare Israel’s campaign in the Gaza Strip a genocide against Palestinians, the officials said.

But on Monday, while traveling in Asia, Mr. Blinken signed off on the genocide determination.

Under international law, the finding does not oblige the U.S. to take action, although officials said the sanctions provide some immediate teeth to the measure. More broadly, experts said it might propel a new drive for accountability in a war that has caused up to 150,000 deaths, the U.S. envoy to Sudan, Tom Perriello, estimated last year.

The genocide determination may also bring new scrutiny to the role of the United Arab Emirates, which has supplied the R.S.F. with smuggled weapons and powerful drones, according to American officials and visual evidence collected by The New York Times.

Mr. Blinken said the finding did not mean the United States was supporting Sudan’s army in the war. “Both belligerents bear responsibility for the violence and suffering in Sudan and lack the legitimacy to govern a future peaceful Sudan,” he said.

Critics who have accused the United States of acting too slowly on Sudan welcomed the finding, with caveats.

“This attempt to position the administration on the right side of history won’t work,” Cameron Hudson, a former American diplomat and Sudan expert at the Center for Strategic and International Studies, said on social media of the Biden administration. “It’s too late and too many people have died for that to happen.”