Russian missile strikes hit Ukraine's capital and other cities Saturday, as Moscow said its troops had cleared the urban area of Mariupol and only a small contingent of Ukrainian fighters remained inside a steelworks plant in the besieged southern port.
Russia's claim to have all but taken control of Mariupol, scene of the war's heaviest fighting and worst humanitarian catastrophe, could not be independently verified. It would be the first major city to have fallen to Russian forces since the February 24 invasion.
Ukrainian President Volodymyr Zelenskyy said Saturday the situation in the besieged port remained extremely severe and Kyiv was in touch with city's defenders every day.
Zelenskyy, speaking in an online address, accused Russia of trying to wipe out the city's inhabitants but did not address Moscow's claim earlier in the day that its troops had cleared the entire urban area of Mariupol of Ukrainian forces.
"The situation is very difficult" in Mariupol, President Volodymyr Zelenskyy told the Ukrayinska Pravda news portal. "Our soldiers are blocked; the wounded are blocked. There is a humanitarian crisis. … Nevertheless, the guys are defending themselves."
As Russia launched more long-range attacks following the sinking of its Black Sea fleet's flagship, Moscow said its warplanes had struck a tank repair factory in Kyiv. An explosion was heard, and smoke rose over the southeastern Darnytskyi district. The mayor said at least one person was killed and medics were fighting to save others.
The Ukrainian military said Russian warplanes that took off from Belarus had fired missiles at the Lviv region near the Polish border and four cruise missiles were shot down by Ukrainian air defenses.
The western city has been relatively unscathed so far and serves as a haven for refugees and international aid agencies.
In the port city of Mariupol, Reuters journalists in Russian-held districts reached the Ilyich steelworks, one of two metals plants where defenders have held out in underground tunnels and bunkers. Moscow claimed to have captured it Friday.
The factory was reduced to a ruin of twisted steel and blasted concrete, with no sign of defenders present. Several bodies of civilians lay scattered on nearby streets.
The RIA news agency said as of Saturday, Ukrainian forces in the city had lost more than 4,000 people.
The governor of Kharkiv province in the east said at least one person had been killed and 18 were injured in a missile strike.
In Mykolaiv, a city close to the southern front, Russia said it had struck a military vehicle repair factory.
Retaliation after ship sinks
The attacks followed Russia's announcement Friday that it would intensify long-range strikes in retaliation for unspecified acts of "sabotage" and "terrorism," hours after it confirmed the sinking of its Black Sea flagship, the Moskva.
Kyiv and Washington say the ship, whose sinking has become a symbol of Ukrainian defiance, was hit by Ukrainian missiles. Moscow says it sank after a fire and that its crew of around 500 were evacuated.
Russia's Defense Ministry published video of the head of the navy, Admiral Nikolai Yevmenov, meeting on a parade ground with about a hundred sailors it said were members of the crew.
A month and a half into President Vladimir Putin's invasion of Ukraine, Russia is trying to capture territory in the south and east after withdrawing from the north following an assault on Kyiv that was repelled at the capital's outskirts.
Mariupol 'will always be Ukrainian'
Mariupol is the main port of the Donbas, a region of two provinces in the southeast that Moscow demands be fully ceded to separatists.
The owner of both steelworks factories in Mariupol, Ukraine's richest man, Rinat Akhmetov, vowed to rebuild the city.
"Mariupol has been and will always be a Ukrainian city," Akhmetov told Reuters.
Ukraine says it has so far held off Russian advances elsewhere in the Donbas regions of Donetsk and Luhansk, where at least one person was killed in shelling overnight.
In the front-line Luhansk town of Lysychansk, civilians fled for safety from incoming shells as thick smoke rose from a blackened shop and burned-out cars.
Ukraine gained the upper hand in the early phase of a war, in part by successfully deploying mobile units armed with anti-tank missiles supplied by the West against Russian armored convoys confined to roads by muddy terrain.
But Putin appears determined to capture more Donbas territory to claim victory in a war that has left Russia subject to increasingly punitive Western sanctions and with few allies.
Zelenskyy told Ukrainian reporters the world should prepare "in a number of ways" for the possibility Russia might use nuclear weapons. He did not give evidence for the assertion.
Last month, Kremlin spokesman Dmitry Peskov said Russia would resort to nuclear weapons only in the case of a "threat to the existence" of the country, and not as a result of the Ukraine conflict.
An adviser to Zelenskyy said the country needed a swifter supply of weapons from its European Union partners.
"Ukraine needs weapons. Not in a month. Now," Mykhailo Podolyak said in a Twitter post.
Russian defense officials said its anti-aircraft systems in the Odesa region shot down a Ukrainian transport plane delivering weapons supplied by Western governments. It did not provide any evidence. There was no immediate comment from Kyiv.
Zelenskyy said about 2,500-3,000 Ukrainian troops have been killed so far and up to 20,000 Russian troops.
Moscow has given no updates on its casualties since March 25, when it said 1,351 had died. Western estimates of Russian losses are many times higher.
Ukraine says civilian deaths are impossible to count, estimating at least 20,000 were killed in Mariupol alone.
Overall, around a quarter of Ukrainians have been driven from their homes, including a tenth of the population that has fled abroad.