The United States vowed to reinforce Europe's defenses in the wake of Russia's invasion of Ukraine, as NATO declared Moscow the West's greatest threat -- prompting Vladimir Putin to lash out at the alliance's "imperial ambitions".
Meeting in Madrid Wednesday, NATO leaders said Russia "is the most significant and direct threat to allies' security and to peace and stability in the Euro-Atlantic area".
This came as NATO officially invited Sweden and Finland to join the alliance, and US President Joe Biden announced new deployments of US troops, ships and planes, AFP said.
Biden said that the US move was exactly what Russian President Putin "didn't want" -- and Moscow, facing fierce resistance from Ukrainian forces equipped with Western arms, reacted with predictable fury.
Putin accused the alliance of seeking to assert its "supremacy", telling journalists in the Turkmenistan capital of Ashgabat that Ukraine and its people are "a means" for NATO to "defend their own interests."
"The NATO countries' leaders wish to... assert their supremacy, their imperial ambitions," the Russian president added.
NATO leaders have funneled billions of dollars of arms to Ukraine and faced a renewed appeal from President Volodymyr Zelensky for more long-range artillery.
"Ukraine can count on us for as long as it takes," NATO chief Jens Stoltenberg said at the summit, which ends Thursday, announcing a new strategic overview that focuses on the Moscow threat.
The document, updated for the first time since 2010, warned that the alliance "cannot discount the possibility" of an attack on its members.
- 'No problem' -
"Today in Madrid, NATO proved it can take difficult but essential decisions. We welcome a clear-eyed stance on Russia, as well as the accession for Finland and Sweden," Ukraine's foreign minister Dmytro Kuleba said.
But Putin dismissed NATO's invites to Finland and Sweden, which abandoned decades of military non-alignment in response to the invasion, as "no problem".
Russian missiles continued to rain down across Ukraine. Zelensky said that a missile strike on the southern city of Mykolaiv destroyed a five-storey building, killing at least five people.
The city of Lysychansk in the eastern Donbas region -- the current focus of Russia's offensive -- was also facing sustained bombardment.
The frequency of the shelling there is "enormous," the regional governor of Lugansk, Sergiy Gaiday, said in televised comments Wednesday, adding that the evacuation of some 15,000 civilians still in the city "might be dangerous at the moment."
In Kremenchuk, the town where a Russian missile on Monday destroyed a shopping center and killed at least 18 civilians, clearing operations continued.
A giant crane was working near the site of impact, and in the rubble-strewn parking area shopping trolleys piled with clothes and household goods lay abandoned.
At a hospital in the city, some of the wounded recalled the moment of the attack.
"We didn't hear the sound of the missile hit -- a sudden clap, flash, and we got blown away," said Petr Ozhereliev, an employee at the mall.
"I guess I lost consciousness, because when I woke up I was crawling out of the rubble."
Western leaders have dubbed the Kremenchuk strike a war crime. Russia says it hit a depot storing Western arms, and Putin on Wednesday denied Moscow's forces were responsible for the attack.
Meanwhile, Ukrainian officials said that 144 of their soldiers, most of them former defenders of the Azovstal steelworks in the southern port city of Mariupol, had been freed in a prisoner swap with Moscow.
- Theatre strike 'war crime' -
Moscow's invasion triggered massive economic sanctions and a wave of support for Zelensky's government, including deliveries of advanced weapons, as well as the reinforcement of Europe's defenses.
Washington has announced that it will shift the headquarters of its 5th Army Corps to Poland.
An army brigade will rotate in and out of Romania, two squadrons of F-35 fighters will deploy to Britain, US air defense systems will be sent to Germany and Italy, and the fleet of US Navy destroyers in Spain will grow from four to six.
Britain also pledged another $1.2 billion in military aid for Ukraine on Wednesday, including air defense systems and drones.
In a report released Thursday, Amnesty International said a theatre sheltering civilians destroyed in March in the besieged city of Mariupol was likely hit by a Russian airstrike in a war crime.
"Until now, we were speaking about an alleged war crime. Now we can clearly say it was one, committed by the Russian armed forces," Oksana Pokalchuk, head of Amnesty's Ukraine branch, told AFP.
Nevertheless, the group also found the death toll may have been smaller than initially believed. Amnesty believes at least a dozen people died in the attack although it is likely many additional fatalities remain unreported.
Mariupol city authorities had provided an initial estimate of around 300 deaths.