Ukraine Live Updates: ‘This Man Cannot Remain in Power,’ Biden Says of Putin

“In this battle, we need to be cleareyed,” Mr. Biden said in front of a crowd waving Polish, Ukrainian and American flags. “This battle will not be won in days or months, either. We need to steel ourselves for the long fight ahead.”

While declaring that “the Russian people are not our enemy,” he unleashed an angry tirade against Mr. Putin’s claim that the invasion of Ukraine is intended to “de-Nazify” the country. Mr. Biden called that justification “a lie,” noting that President Volodymyr Zelensky of Ukraine is Jewish and that his father’s family was killed in the Holocaust.

“It’s just cynical,” Mr. Biden said. “He knows that. And it’s also obscene.”

It was not immediately clear whether Mr. Biden’s apparent call for the ouster of Mr. Putin was one of the off-the-cuff remarks for which he is known or a calculated jab, one of many in the speech. But it risks confirming Russia’s central propaganda claim that the West, and particularly the United States, is determined to destroy Russia.

The White House immediately sought to play down the remark. “The president’s point was that Putin cannot be allowed to exercise power over his neighbors or the region,” a White House official told reporters. “He was not discussing Putin’s power in Russia, or regime change.”

Earlier in the day, Mr. Biden stood shoulder-to-shoulder with the Polish president, Andrzej Duda, a key NATO ally, and assured him that the United States considered its support for the alliance to be a “sacred obligation.”

In meeting with Mr. Duda at the presidential palace in Warsaw, Mr. Biden was hoping to bolster an ally on Ukraine’s western border that has served as a conduit for Western arms and has absorbed more than 2 million refugees fleeing the violence, more than any other country in Europe.

“America’s ability to meet its role in other parts of the world rests upon a united Europe,” Mr. Biden said.

While Poland’s right-wing, populist government has been embraced by Washington and Brussels as a linchpin of Western security, it has provoked quarrels with both in the past. Mr. Duda, however, thanked Mr. Biden for his support, saying that Poland stood ready as a “serious partner, a credible partner.”

At a stadium in Warsaw, Mr. Biden met with Ukrainian refugees in his first personal encounter with some of the civilians ensnared in a catastrophic humanitarian crisis caused by weeks of indiscriminate Russian shelling of Ukrainian cities and towns.

After speaking with the refugees, including several from the city of Mariupol, which has been flattened by Russian shelling, Mr. Biden called Mr. Putin “a butcher.”

The comment prompted a retort from Dmitri S. Peskov, a Kremlin spokesman, who told TASS, the Russian state-owned news agency, that “such personal insults narrow the window of opportunity” for bilateral relations with the Biden administration.

Mr. Biden also met with Ukrainian ministers in his first in-person meeting with the country’s top leaders since the Russian invasion began on Feb. 24, part of what American officials hope will be a powerful display of the United States’ commitment to Ukrainian sovereignty.

“We did receive additional promises from the United States on how our defense cooperation will evolve,” Dmytro Kuleba, Ukraine’s foreign minister, told reporters, the Reuters news agency reported.

But Mr. Biden gave no indication that the United States was willing to budge from its previous rejection of Ukrainian requests to establish a no-fly zone over the country or to provide it with the MIG-29 warplanes that Poland offered some weeks ago.

As Mr. Biden visited Poland, two missiles struck Lviv, a western Ukrainian city about 50 miles from the Polish border, rattling residents who ran into underground shelters as smoke rose into the sky. Lviv’s mayor said a fuel storage facility was on fire, and a regional administrator said five people had been injured.

Although Russian missiles hit a warplane repair factory near Lviv on March 18, the city, which had 700,000 residents before many of them fled the war, has otherwise been spared the airstrikes and missile attacks that have hammered other Ukrainian population centers.

Mr. Biden ended his trip one day after a senior Russian general suggested that the Kremlin might be redefining its goals in the war by focusing less on seizing major cities and instead targeting the eastern Donbas region, where Russia-backed separatists have been fighting Ukrainian forces for eight years.

Mr. Biden’s administration was quietly exploring the implications of the statement by the Russian general, Sergei Rudskoi, which indicated that Mr. Putin might be looking for a way out of the brutal invasion he launched with confidence and bravado a month ago.

Western intelligence agencies have in recent weeks picked up chatter among senior Russian commanders about giving up the effort to take Kyiv, Ukraine’s capital, and other key areas in the north and west of the country, according to two people with access to the intelligence. Instead, the commanders have talked more narrowly of securing the Donbas region.

It remains unclear, one senior American official said, “whether Putin has signed on” to a strategy that would abandon his grand ambitions for taking control of Ukraine, which he declared in February was not a real country and had been torn from “her own historical territory.” And military analysts have cautioned that the statement could be intended as misdirection while Russian forces regroup for a new offensive.

Only weeks ago, Mr. Putin threatened to fully absorb Ukraine, warning that, “The current leadership needs to understand that if they continue doing what they are doing, they risk the future of Ukrainian statehood.”

Administration officials said a Russian retreat to the Donbas would amount to a remarkable failure for Mr. Putin, who has drawn international scorn for an invasion that has isolated Russia and plunged its economy into disarray under the weight of global sanctions.

In one sign that Russia may be increasingly focused on the Donbas region, a United States official warned on Friday that Russian mercenaries with combat experience in Syria and Libya were gearing up for an active combat role in eastern Ukraine.

The number of mercenaries with the notorious Wagner Group was expected to more than triple, to at least 1,000 fighters from about 300 a month ago, just before the invasion, the official said.

Hoping to rally his country and encourage negotiations with Moscow, Mr. Zelensky said that the success of a Ukrainian counteroffensive that began two weeks ago was “leading the Russian leadership to a simple and logical idea: Talk is necessary.”

“The conversation must be meaningful,” Mr. Zelensky said in an overnight video address. “Ukrainian sovereignty must be guaranteed. Ukraine’s territorial integrity must be ensured.”

For the moment, large portions of Ukraine remain a battleground in what has increasingly come to resemble a bloody stalemate between the smaller Ukrainian army and Russian troops that have struggled with logistical problems.

On Saturday, Russian forces entered the small northern city of Slavutych, near the Chernobyl nuclear power plant, where they seized the hospital and briefly detained the mayor, a regional military official said.

In response, dozens of residents unfurled the Ukrainian flag in front of city hall and chanted, “glory to Ukraine,” prompting Russian troops to fire into the air and throw stun grenades, according to videos and the official, Oleksandr Pavliuk.

Slavutych, which had about 25,000 residents before the war, was built for evacuees from the 1986 Chernobyl nuclear disaster and is home to many of the plant’s workers. It is near the Belarusian border in an area that Russian troops have mostly controlled.

The International Atomic Energy Agency had warned that Russian assaults on the city were jeopardizing workers’ ability to operate and ensure safety at the Russia-controlled plant.

On Friday, Ukraine’s defense ministry claimed that a top Russian military commander, Lt. Gen. Yakov Rezantsev, had been killed near the city of Kherson in southern Ukraine. He was the seventh Russian general to fall in battle, according to Ukrainian officials.

In the latest instance of nuclear saber-rattling, Dmitri A. Medvedev, the vice chairman of Russia’s Security Council, restated Moscow’s willingness to use nuclear weapons against the United States and Europe if its existence was threatened.

“No one wants war, especially given that nuclear war would be a threat to the existence of human civilization,” Mr. Medvedev told Russia’s state-run RIA Novosti news agency in excerpts from an interview published on Saturday.

“All our people know that the targets of nuclear weapons of NATO countries are facilities on the territory of our country, and our warheads are aimed at targets located in Europe and the United States of America,” Mr. Medvedev was quoted as saying. “But that is life. Therefore, one should always think about this and pursue a responsible policy.”

Michael D. Shear and David E. Sanger reported from Warsaw and Michael Levenson from New York. Reporting was contributed by Megan Specia from Krakow, Poland, Anton Troianovski from Istanbul, Valerie Hopkins from Lviv, Ukraine, Eric Schmitt from Washington and Apoorva Mandavilli from New York.