KRAKOW, Poland — President Vladimir V. Putin of Russia faced a series of setbacks Monday over the Ukraine invasion, as his faltering military appeared forced to further shrink its goals and an emboldened NATO practiced war games with the alliance’s two newest applicants on his country’s doorstep.
To make matters worse for Mr. Putin, his own allies in Russia’s counterpart to NATO failed to rally around him at a summit meeting in Moscow, leading to the optics of an increasingly isolated Kremlin in full display on Russia’s state-run television.
One of the few bright spots for Mr. Putin was the decision by Ukraine’s military late Monday to finally end the resistance of holdout fighters at the Azovstal steel mill in the southeast port of Mariupol, which had been under Russian siege for weeks.
Outgunned, wounded and starving, the fighters had become heroes to many Ukrainians, but were evacuated in what amounted to a surrender, with the Ukrainian military saying that 264 service members, 53 of them “seriously wounded,” had been taken by bus to areas controlled by Russian forces.
President Volodymyr Zelensky of Ukraine said the decision had been meant “to save the lives of our boys.”
But that Russian victory in Mariupol came as Mr. Putin faced what could be the largest expansion of NATO in decades.
The image of Mr. Putin on his back foot was fueled further by two of the biggest names in global business — McDonald’s and Renault — announcing their departure from Russia, adding to the corporate exits that, combined with Western sanctions, have delivered a severe setback to the country’s economy.
And in what would be a change of position, Mr. Putin seemed to soften his strong objections to NATO membership for Finland and Sweden, which participated in its military exercises in the Baltics on Monday. Only last week, Mr. Putin had warned the two Nordic countries that joining NATO would be a mistake.
France, Denmark, Norway and Iceland were among the NATO members on Monday that said they welcomed Sweden and Finland to join.
Still, their applications could take time.
Turkey, which has accused the two applicants of sheltering anti-Turkish Kurd extremists, has held out the possibility of using its leverage for concessions before approving their memberships, which require consent from all 30 NATO countries. Secretary of State Antony J. Blinken has expressed confidence that “we will reach consensus.”
In another signal of Western resolve to confront Russia, the Senate voted 89-11 Monday night to advance the $40 billion Ukraine aid package approved last week by the House, setting up a vote to send the measure to President Biden’s desk as early as Thursday.
Taken together, the developments on Monday created one of the starkest contrasts yet between the Russia of now versus that of Feb. 24, when columns of Russian tanks and tens of thousands of its soldiers poured into Ukraine from the east, north and south, in what seemed at the time like an unstoppable juggernaut that could end Ukraine’s independence as a sovereign country.
It soon became clear that despite Russia’s destructive and indiscriminate aerial bombardments, its vaunted armed forces faced major battlefield flaws and suffered heavy losses, and that Ukraine’s outnumbered defenders were in many places driving them back, helped by an outpouring of Western military support.
Within weeks, the Russians were forced to retreat from the Kyiv area in the north and refocus their invasion on seizing the Luhansk and Donetsk provinces that form the Donbas region of eastern Ukraine, where Russian-backed separatists have been fighting since 2014.
But Russia’s drive to take Donbas, despite its initial success, now appears to be stumbling as well, military analysts said. Aside from Mariupol, the Russians have yet to seize any significant city there.
In the last week, the Russians retreated from the suburbs of the northeast city of Kharkiv, less than 40 miles from the Russian border. In a symbolic signal of their recent battlefield successes, a small number of Ukrainian troops photographed themselves Monday on the border, having evaded Russian forces nearby.
The Institute for the Study of War, a Washington-based group, said in its latest appraisal that Russian forces had likely abandoned their goal of encircling tens of thousands of Ukrainian soldiers in Donbas and had halted their own attempt to seize Donetsk, focusing instead on capturing Luhansk.
In what appeared to be a further setback, the institute also said Russia had likely run out of combat-ready reservists, forcing it to integrate forces from private military companies and militias with its regular army.
Western military analysts have repeatedly cautioned that Russia remains by far the bigger force, and that the war could last for months or years. Russia still controls a swath of southern Ukraine seized early in the invasion and has blockaded Black Sea ports, choking Ukraine’s economic lifelines.
But Russia’s miscalculations and growing isolation because of the war have overshadowed its gains.
Among the most visible signs of backlash against Russia were the large-scale NATO exercises in Estonia, the former Soviet republic — precisely the type of military display that the Kremlin sees as a threat. While the exercises had long been planned, their significance was elevated by the participation of Finland and Sweden and by the host of the exercises, Estonia, which shares a border with Russia.
For Estonia’s prime minister, Kaja Kallas, whose parents grew up in the repressive Soviet era, Ukraine’s struggle cannot be concluded with the appeasement of Russia.
“I only see a solution as a military victory that could end this once and for all, and also punishing the aggressor for what he has done,” Ms. Kallas said in an interview with The New York Times. Otherwise, she said, “we go back to where we started.”
The NATO drill, called Hedgehog, was one of the largest in Estonia since it became independent in 1991, with 15,000 personnel from 14 countries.
Russia-Ukraine War: Key Developments
In Moscow, where Mr. Putin convened a meeting of Russia’s answer to NATO — the six-member Collective Security Treaty Organization — only one member, Belarus, spoke up to support him on Ukraine.
It was supposed to be a celebratory meeting to commemorate the group’s founding 30 years ago. But it turned into a demonstration of discord among some of Mr. Putin’s friendly neighbors.
Speaking first in the televised portion of the summit, President Aleksandr G. Lukashenko of Belarus — who has supported Mr. Putin’s war but has not sent troops — criticized other members for having insufficiently backed Russia and Belarus in the face of Western sanctions.
He pointed to the alliance’s decision to send forces to Kazakhstan in January to protect the government from protests — yet argued it had left Russia largely on its own over Ukraine.
“Are we just as connected by bonds of solidarity and support now?” he asked, after mentioning the alliance’s support of the Kazakh government. “Maybe I’m wrong, but as recent events have shown, it seems the answer is no.”
Kazakhstan has said it would not help Russia circumvent international sanctions. In a United Nations vote on March 2 condemning the invasion of Ukraine, Belarus was the only post-Soviet country to take Russia’s side.
“Look at how monolithically the European Union votes and acts,” Mr. Lukashenko said at Monday’s summit, sitting at a round table with the other leaders. “If we are separate, we’ll just be crushed and torn apart.”
As if to confirm Mr. Lukashenko’s point, the leaders of the other members — Armenia, Kazakhstan, Kyrgyzstan and Tajikistan — did not mention Ukraine in their televised remarks.
The Ukraine invasion has put those countries in a tough spot. They all have close economic and military ties to Russia, but Mr. Putin’s invasion of a sovereign neighbor sets a foreboding precedent for countries looking to diversify their foreign policy beyond Moscow.
Mr. Putin, speaking at the summit, again tried to justify his invasion by falsely claiming that “neo-Nazism has long been rampant in Ukraine.” But he took a more measured tone in discussing the likely accession of Sweden and Finland to NATO — the latest evidence that Mr. Putin appears to be trying to limit, for now, an escalation of his conflict with the West.
“Russia, I would like to inform you, dear colleagues, has no problem with these states,” Mr. Putin said, adding that NATO’s expansion to include Sweden and Finland poses “no direct threat to us.”
Still, he did not rule out unspecified retaliation if Finland and Sweden were to expand their “military infrastructure” as NATO members, warning that “we will look at what that will be based on the threats that are created.”
Marc Santora reported from Krakow, Poland, Anton Troianovski and Rick Gladstone from New York, and Matthew Mpoke Bigg from London. Reporting was contributed by Steven Erlanger from Tallinn, Estonia, Andrew E. Kramer and Valerie Hopkins from Kyiv, Ukraine, Eric Schmitt and Catie Edmondson from Washington, Cassandra Vinograd from London, Lauren Hirsch from New York, Liz Alderman from Paris, and Neil MacFarquhar and Safak Timur from Istanbul.