Russian troops have abandoned their positions on a captured Ukrainian island, a major setback to their invasion effort that weakens their blockade of Ukraine's ports, defence officials said on Thursday.
The news from the Black Sea came as NATO leaders wrapped up their summit in Madrid, with US President Joe Biden announcing $800 million in new weapons to help Ukraine fight off Russia's invasion.
"We are going to stick with Ukraine, and all of the alliance are going to stick with Ukraine, as long as it takes to make sure they are not defeated by Russia," he said.
Russian President Vladimir Putin's foreign minister, Sergei Lavrov, compared the new diplomatic low to the return of the Cold War, telling reporters: "As far as an Iron Curtain is concerned, essentially it is already descending… The process has begun."
But there may be a possible opening: Indonesia's President Joko Widodo said, after meeting Putin in Moscow, that he had given the Russian leader a message from his Ukrainian counterpart, Volodymyr Zelensky.
Snake Island became a symbol of Ukrainian resistance in the first days of the war, when the rocky outcrop's defenders told a Russian warship that called on them to surrender to "go f*ck yourself", an incident that spurred a defiant meme.
It was also a strategic target, sitting aside shipping lanes near Ukraine's port of Odessa.
Russia had attempted to install missile and air defence batteries while under fire from drones.
Now, however, Ukraine has begun to receive longer range missiles and artillery, and the Russian position on Snake Island seems to have become untenable.
British Prime Minister Boris Johnson warned the Russian president that any eventual peace deal would be on Ukraine's terms.
"In the end, it will prove impossible for Putin to hold down a country that will not accept his rule," he said.
"We've seen what Ukraine can do to drive the Russians back. We've seen what they did around Kyiv and Kharkiv, now on Snake Island."
The Russian defence ministry statement described the retreat as "a gesture of goodwill" meant to demonstrate that Moscow will not interfere with UN efforts to organise protected grain exports from Ukraine.
But Kyiv claimed it as a win.
"They always downplay their defeats this way," Ukraine's Foreign Minister Dmytro Kuleba said on Twitter.
"I thank the defenders of Odessa region who took maximum measures to liberate a strategically important part of our territory," Valeriy Zaluzhny, the Ukraine military's commander-in-chief, said on Telegram.
In peacetime, Ukraine is a major agricultural exporter, but Russia's brutal invasion has damaged farmland and seen Ukraine's ports seized, razed or blockaded – threatening grain importers in Africa with famine.
Western powers have accused Putin of using the trapped harvest as a weapon to increase pressure on the international community, and Russia has been accused of stealing grain.
On Thursday, a ship carrying 7,000 tonnes of grain sailed from Ukraine's occupied port of Berdyansk, said the regional leader appointed by the Russian occupation forces.
Evgeny Balitsky, the head of the pro-Moscow administration, said Russia's Black Sea ships "are ensuring the security" of the journey, adding that the port had been de-mined.
Separately, the Russian defence ministry said its forces are holding more than 6,000 Ukrainian prisoners of war who have been captured since the 24 February invasion.
The conflict in Ukraine has dominated the NATO summit in Madrid, where the 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 Biden announced new deployments of US troops, ships and planes to Europe.
Biden said the US move was exactly what Putin "didn't want" – and Moscow, facing fierce resistance from Ukrainian forces equipped with Western weapons, reacted with predictable fury.
Putin on Wednesday 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," Putin added.
German Chancellor Olaf Scholz dismissed Putin's comments as "ridiculous" and said the Russian leader "has made imperialism the goal of his politics".
NATO leaders have funnelled billions of dollars of arms to Ukraine and faced a renewed appeal from Zelensky for more long-range artillery.
"Ukraine can count on us for as long as it takes," NATO chief Jens Stoltenberg told the summit, as he announced a new strategic overview that focuses on the Moscow threat.
The document, updated for the first time since 2010, warned the alliance "cannot discount the possibility" of an attack on its members.
Russian missiles continued to rain down on cities across Ukraine.
In the southern city of Mykolaiv, rescuers found the bodies of seven slain civilians in the rubble of a destroyed building, emergency services said.
The city of Lysychansk in the eastern Donbas region – the current focus of Russia's offensive – is also facing sustained bombardment.
The situation in Lysychansk – the last major city the Russians need to take over in the Lugansk region – was "extremely difficult" with relentless shelling making it impossible to evacuate civilians, regional governor Sergiy Gaiday said.
"There is a lot of shelling… The Russian army is approaching from different directions," he said in a video posted on Telegram.
Russia's forces remain at the outskirts of the city where there is currently no street fighting, he said.
Gaiday dismissed claims by pro-Russian separatists fighting alongside Moscow's forces who claim to control half of the city situated across the river from neighbouring Severodonetsk, which was captured by the Russian army last week.
The United Nations humanitarian coordinator in Ukraine said on Thursday 16 million people in Ukraine were in need of humanitarian aid.
Also on Thursday, Russia summoned Britain's ambassador to Moscow to protest at Johnson's "offensive" remarks about Putin.
Johnson had said on Tuesday that Putin would not have started the war in Ukraine if he was a woman and said the military operation was "a perfect example of toxic masculinity".
The Russian foreign ministry said: "In polite society, it is customary to apologise for remarks of this kind."