Russia bombed a factory in Kyiv overnight which it claims made the missiles that sunk the Moskva, as the Kremlin vowed to step up attacks on the Ukrainian capital.
Heavy explosions were seen overnight in Kyiv before Russia's Ministry of Defence said early Friday that it had destroyed the 'Vizar' plant which manufactures anti-ship missiles and other Ukrainian rockets.
The attack came just a day after the Moskva - the flagship of Russia's Black Sea fleet - was sunk after a fire an explosion on board that Ukraine says was caused when it was shot by two cruise missiles. Moscow says only that the cause is being 'investigated'.
Meanwhile President Zelensky, speaking in a Thursday night address to the nation, praised the herosim of Ukrainians in holding out against Russia's invasion for 50 days - in spite of warnings they would last just five.
Russian Defence Ministry posts video of strikes on Kyiv factory
Russia says it blew up a Ukrainian munitions factory near Kyiv overnight using cruise missiles fired from ships in the Black Sea (pictured being launched)
Moscow says the factory was used to manufacture the same kinds of missiles that were used to sink the Moskva, its Black Sea flagship, on Thursday
President Zelensky addressed Ukrainians overnight, praising their heorism in resisting Russia for 50 days when the world expected them to last just five
Russia told the US to stop sending weapons to Ukraine, warning of 'unpredictable consequences' if it continues to do do.
The warning was delivered in the form of an official diplomatic note, which was seen by the Washington Post.
It said that American and NATO shipments of the 'most sensitive' weapons were 'adding fuel' to the conflict, which is now nearing its second month.
The two-page note was delivered after Biden had agreed to a new $800million delivery of military aid to Ukraine, including heavy artillery and shells, helicopters and armoured personnel carriers.
'What the Russians are telling us privately is precisely what we’ve been telling the world publicly — that the massive amount of assistance that we’ve been providing our Ukrainian partners is proving extraordinarily effective,' a senior US official said about the note.
Zelensky said he remembered the first day of the invasion when many world leaders, unsure whether Ukraine could survive, advised him to leave the country.
He added: 'But they didn't know how brave Ukrainians are, how much we value freedom and the possibility to live the way we want.'
Zelensky told Ukrainians on Thursday they should be proud of having survived 50 days under Russian attack when the Russians 'gave us a maximum of five'.
He called it 'an achievement of millions of Ukrainians, of everyone who on February 24 made the most important decision of their life - to fight'.
Russia's defence ministry warned early Friday that it will step up attacks on Kyiv in the coming days, in response to Ukrainian strikes on Russian territory.
A village in Russia's border region with Belarus, which houses a military base, was struck Thursday - coming after explosions at an ammo dump and oil facility in Belgorod, an along a nearby train line.
Images from Belgorod in the early hours of Friday showed anti-aircraft missiles in the sky, suggesting fresh strikes were underway.
Meanwhile, the military claimed to have shot down a Ukrainian Mi-8 helicopter involved in the attack on the Bryansk region near Chernihiv.
Ukraine has not acknowledged carrying out any such strikes, but has also not denied being behind them.
'The number and scale of missile strikes on targets in Kyiv will increase in response to any terrorist attacks or acts of sabotage on Russian territory committed by the Kyiv nationalist regime,' Russia's defence ministry said in a statement.
The explosions came hours after the Russian defence ministry announced that the Moskva, the flagship of Russia's Black Sea Fleet, had sunk while being towed after being badly damaged - reportedly leaving Putin 'livid'.
Amid a ream of bad news for the Russian despot's war, his forces on Friday did appear on the verge of capturing Mariupol - a southern port city that has now been under siege for almost two months.
Local records the sound of terrifying shelling near Kyiv
Heavy explosions were reported to the south of Kyiv overnight, after Russia bombed what it claimed was a missile factory
Heavy shelling and explosions believed to be in Kyiv overnight
The defence ministry claimed its troops had seized control of the Ilyum Steel Works, a huge industrial complex in the centre of Mariupol where marines and troops of the Azov Battalion were making their last stand.
If confirmed, it would mean Mariupol is on the verge of falling into Russian hands. It would be the largest city yet captured by Putin's men, albeit at the cost of near-totally destroying it.
While some forces in the area are likely to continue fighting guerilla operations against Russian forces, the defeat of the city's defences would also free up troops to join an expected assault on Ukraine's east.
British Intelligence on Thursday assessed that the fight for Mariupol is currently tying up 'significant numbers of Russian troops and equipment'.
Separately, the Russian defence ministry said Friday its strategic rocket forces 'eliminated up to 30 Polish mercenaries' in a strike on the village of Izyumskoe, not far from the city of Kharkiv in northeastern Ukraine.
It said the mercenaries belonged to 'a private Polish military company', but did not say whether any Ukrainian troops were also killed.
The reported rocket strike was one of the biggest against foreign targets in Ukraine since another missile killed what the Russian military claimed was up to 180 foreign mercenaries in Western Ukraine last month.
Russia invaded on February 24 and has lost potentially thousands of fighters in the weeks since. The conflict has killed untold numbers of Ukrainian civilians and forced millions more to flee.
It came as the head of the UN World Food Programme (WFP) said people are being 'starved to death' in the besieged Ukrainian city of Mariupol and he predicted the country's humanitarian crisis is likely to worsen as Russia intensifies its assault.
CCTV footage appears to show strike on Ukrainian missile factory
Ukraine is continuing to take the attack to Russia as its invasion falters - sinking the Moskva, striking Belgorod, and battling in eastern Ukraine. But Moscow claims its troops are on the verge of taking Mariupol, which has now been under siege for almost two months
Anti-air missiles are seen in the skies over Belgorod, Russia, on Friday - suggesting the city has once again come under attack by Ukraine
WFP executive director David Beasley also warned in an interview Thursday with The Associated Press in Kyiv that Russia's invasion of grain-exporting Ukraine risks destabilising nations far from its shores and could trigger waves of migrants seeking better lives elsewhere.
His fears were shared by the US ambassador to the United Nations, who accused Russia of making the precarious food situation in Yemen and elsewhere worse by invading Ukraine, calling it 'just another grim example of the ripple effect Russia's unprovoked, unjust, unconscionable war is having on the world's most vulnerable'.
Linda Thomas-Greenfield told a UN Security Council meeting on war-torn Yemen on Thursday the WFP had identified the Arab world's poorest nation as one of the countries most affected by wheat price increases and lack of imports from Ukraine.
Russia's deputy UN ambassador Dmitry Polyansky replied: 'The main factor for instability and the source of the problem today is not the Russian special military operation in Ukraine, but sanctions measures imposed on our country seeking to cut off any supplies from Russia and the supply chain, apart from those supplies that those countries in the West need, in other words energy.'
The sharp exchange took place a day after a UN taskforce warned the war threatens to devastate the economies of many developing countries that are now facing even higher food and energy costs and increasingly difficult financial conditions.
Kyiv residents and business owners clean up after shelling