Russia pounded a Ukrainian rocket factory after losing an iconic warship in the Black Sea, as the Pentagon on Friday backed Kyiv's claim to have sunk the Moskva with cruise missiles.
The Vizar plant, near the capital's international airport, was seriously damaged in the overnight strikes, an AFP journalist saw.
Russia said it had used sea-based long-range missiles to hit the factory, which Ukraine's state weapons manufacturer says produced Neptune cruise missiles.
"There were five hits. My employee was in the office and got thrown off his feet by the blast," Andrei Sizov, a 47-year-old owner of a nearby wood workshop, told AFP.
"They are making us pay for destroying the Moskva," he said. It was the first major Russian strike around the Ukrainian capital in over two weeks.
A Pentagon official briefing reporters said Ukraine had hit the Moskva with two Neptunes -- contradicting Russia's claim that the ship lost balance in rough seas as it was towed to port after ammunition exploded.
The Moskva had been leading Russia's naval effort in the seven-week conflict, and the fate of its crew of over 500 was uncertain.
The Pentagon official said survivors were observed being recovered by other Russian vessels, but Ukraine authorities said bad weather had made rescue operations impossible.
The Russian fleet in the Black Sea has been blockading the besieged port city of Mariupol, where Russian officials say they are in full control although Ukrainian fighters are still holed up in the city's fortress-like steelworks.
In the capital, Kyiv regional governor Oleksandr Pavliuk said there were at least two other Russian strikes on the city Friday, adding civilians thinking about returning should "wait for quieter times."
Russian forces last month started withdrawing from around Kyiv as they were redeployed to focus on the east of the country, but the city remains vulnerable to missile strikes.
"The number and scale of missile strikes against targets in Kyiv will increase in response to any terrorist attacks or sabotage committed by the Kyiv nationalist regime on Russian territory," Russia's defence ministry vowed.
President Volodymyr Zelensky warned Friday that Russia could even use nuclear weapons out of desperation as its invasion falters, echoing recent comments by CIA director William Burns.
"They could do it, I mean they can," Zelensky told CNN. "For them, life of the people is nothing."
Burns said that Russia's battlefield setbacks raised the risk that President Vladimir Putin could deploy a tactical or low-yield nuclear weapon to try to regain the initiative.
In their latest move, Russia on Friday alleged Ukraine was preparing a missile strike to hit its own refugees at a railway station in the town of Lozova in the eastern region of Kharkiv.
The allegations echoed Russia's widely-dismissed claim that Kyiv was responsible for a missile strike on April 18 that killed scored at another railway station.
In Kharkiv, Russian strikes killed at least seven, including a child, the region's governor said Friday, as Moscow's forces stepped up attacks in the region.
Outside the city, the village of Borova came under the control of Russian troops and the local administration had to flee, village mayor Alexander Tertychny said on Facebook.
Ukrainian authorities have been urging people in the south and the Donbas area in the east to quickly move west in advance of a large-scale Russian offensive.
Seizing the Donbas region, where Russian-backed separatists control the Donetsk and Lugansk areas, would allow Moscow to create a southern corridor to the occupied Crimean peninsula.
As the war grinds on, the UN's World Food Programme appealed for access to desperate Ukrainians trapped in war zones including Mariupol.
"It's one thing when people are suffering from the devastation of war. It's another thing when they're being starved to death," WFP director David Beasley said in a statement.
Moscow, which invaded Ukraine partly because of deepening ties between Kyiv and NATO, on Friday warned of consequences should Finland and Sweden join the US-led defence alliance.
The two countries are considering joining NATO after Russia's devastating move into neighbouring Ukraine.
"They will automatically find themselves on the NATO frontline," Russian foreign ministry spokeswoman Maria Zakharova said.
Shortly afterwards, Finland's European Affairs Minister Tytti Tuppurainen said it was "highly likely" that her country would apply for NATO membership.
"The people of Finland, they seem to have already made up their mind and there is a huge majority for the NATO membership," she told Britain's Sky News.
Unlike Sweden, Finland neighbours Russia, from which it declared independence in 1917 after 150 years of Russian rule.
Moscow on Thursday accused Ukraine of sending helicopters to bomb a village in Russia's Bryansk region -- not far from the border with Ukraine -- injuring eight people.
Kyiv denied the helicopter attack, instead accusing Russia of staging the incidents to stir up "anti-Ukrainian hysteria" in the country.