Ukraine acknowledged on Friday it was taking heavy losses in Russia's assault in the east, but said Russia's losses were even worse, as US president Joe Biden called on Congress to send as much as $33 billion (€31.2 billion) to help Kyiv withstand the attack.
The body of a journalist from US-backed broadcaster Radio Liberty was found in rubble in the Ukrainian capital, killed in a missile strike that Russia said had targeted a rocket factory. The strike in central Kyiv coincided with a visit to the city by UN secretary-general Antonio Guterres.
One of the fighters holed up in the steel works in devastated Mariupol, a major target of Russia's invasion, told Reuters he hoped civilians blocked there for weeks would be evacuated after multiple failed attempts.
President Volodymyr Zelenskiy's office had said earlier an operation was planned to get civilians out of the plant and Guterres said intense discussions were underway.
Zelenskiy praised Biden's offer of help, which amounts to nearly 10 times the aid Washington has sent so far since the invasion started on February 24th Moscow calls the war a special military operation. Lawmakers from both parties said they wanted to approve the emergency funding request quickly.
Having failed in an assault on Kyiv in the north of Ukraine last month, Russia is now trying to fully capture two eastern provinces known as Donbas.
Ukraine has acknowledged losing control of some towns and villages there since the assault began last week, but says Moscow's gains have come at a massive cost to a Russian force already worn down from its earlier defeat near the capital.
"We have serious losses, but the Russians' losses are much much bigger...They have colossal losses," presidential adviser Oleksiy Arestovych said, without elaborating. Western officials said Russia had been suffering fewer casualties after narrowing the scale of its invasion but numbers were still "quite high".
Ukrainian officials said Russia was pounding the whole front line in the eastern Donetsk region with rockets, artillery, mortar bombs and aircraft to stop the Ukrainians regrouping.
However, the Russian offensive in Donbas appeared to be behind schedule, a US official said.
"Due to strong Ukrainian resistance, Russian territorial gains have been limited and achieved at significant cost to Russian forces," the British defence ministry said.
By pledging tens of billions of dollars in aid for Ukraine, Biden has dramatically increased US involvement in the conflict.
The United States and its allies are now sending heavy weapons including artillery, with what Washington says is an aim not just to repel Russia's attack but to weaken its armed forces, so it cannot menace its neighbours again.
"We need this bill to support Ukraine in its fight for freedom," Biden said. "It's not cheap - but caving to aggression is going to be more costly."
Zelenskiy thanked Biden and the American people in a tweet.
"We defend common values - democracy and freedom. We appreciate the help. Today it is needed more than ever!"
While the proposed US aid amounts to more than 20 per cent of Ukraine's 2020 GDP, the World Bank estimates the war will cut more than 45 per cent off Ukrainian GDP this year and hit growth elsewhere around the world. Some of Russia's neighbours say they fear Moscow could target them next.
Russia has said the arrival of Western arms into Ukraine means it is now fighting a "proxy war" against Nato. President Vladimir Putin threatened unspecified retaliation this week, while his foreign minister warned of a threat of nuclear war.
A senior US defence official said the United States did not believe that there is a threat of Russia using nuclear weapons or attacking Nato territory despite the escalation in Moscow's rhetoric.
Journalist found in rubble
Prague-based Radio Free Europe/Radio Liberty (RFE/RL), one of the main remaining Russian-language sources for news outside Kremlin control, said the body of producer Vira Hyrych had been found in part of a residential building destroyed by a missile.
"She was going to bed when a Russian ballistic missile hit her apartment in central Kyiv," Ukrainian Foreign Ministry spokesperson Oleg Nikolenko said. "Russia’s barbarism is incomprehensible."
Russia's defence ministry said its high precision long-range missiles had destroyed the production facilities of a rocket plant in Kyiv. A US official confirmed the attack had targeted military production, without saying if those targets were destroyed.
Russia said earlier a diesel submarine in the Black Sea had struck military targets with Kalibr cruise missiles, the first reported such strikes from a submarine.
Ukrainian defence minister Oleksiy Reznikov said the missile attack on Kyiv on Thursday when UN secretary-general Guterres was in the city was "an attack on the security of the Secretary-General and on world security".
The bloodiest fighting and worst humanitarian catastrophe of the war have been in Mariupol, an eastern port reduced to a wasteland by two months of Russian bombardment and siege.
Ukraine says 100,000 civilians remain in the city, which is mostly occupied by Russia. Hundreds of civilians are holed up with last remaining defenders in bunkers beneath the huge steel works.
Zelenskiy's office said an operation was planned on Friday to get civilians out of the plant, giving no details. There was no word of any evacuation by dusk on Friday.
In parts of Mariupol now held by Russian troops, emergency workers were gathering up bodies from the streets. Residents among the blasted ruins recounted the horror they had survived.
"We were hungry, the child was crying when the Grad (multiple rocket launcher) shells were striking near the house. We were thinking, this is it, the end. It can't be described," Viktoria Nikolayeva, 54, who survived the battle with her family in a basement, told Reuters, weeping. - Reuters