The civilian death toll continues to rise in Ukraine, with Russia stepping up its bombardment of several cities as the invasion entered its seventh day.
Four people were killed when homes in the city of Zhytomyr were hit by a Russian cruise missile apparently aimed at a nearby air base overnight, an adviser to the Ukrainian Interior Minister said.
Anton Gerashchenko said homes near the base of the 95th Airborne Brigade in Zhytomyr, 120 kilometres west of the capital Kyiv, had been set on fire.
"So far, four people have died. Including a child," he said.
Moscow warned residents of Kyiv to flee their homes as it rained rockets on Ukraine's second-biggest city, Kharkiv.
Kharkiv's Governor, Oleh Synehubov, said 21 people had been killed by Russian shelling during the past 24 hours. He said another 112 people were wounded in the attacks.
Mayor Ihor Terekhov and local emergency services said four more people had been killed and nine wounded as a barrage of Russian air and rocket strikes pounded Kharkiv on Wednesday morning.
"Kharkiv is a Russian-speaking city. Every fourth person in Kharkiv has relatives in the Russian Federation.
"But the city's attitude to Russia today is completely different to what it ever was before," Mr Terekhov said in an online video statement.
"We never expected this could happen: total destruction, annihilation, genocide against the Ukrainian people — this is unforgivable."
Russian commanders have intensified their bombardment of urban areas in a shift of tactics after their nearly week-long assault stalled.
Ukrainian President Volodymyr Zelenskyy on Wednesday accused Russia of trying to erase his country, referring to an attack on Babyn Yar — the site of a World War II massacre of Jews by German occupation troops and Ukrainian auxiliaries.
But he said the Kremlin would not be able to take his country with bombs and air strikes.
"This strike proves that for many people in Russia, our Kyiv is absolutely foreign," he said.
"They don't know a thing about Kyiv, about our history.
Ukraine's south-eastern port of Mariupol continued to come under constant shelling and the city was struggling to evacuate the injured, Ukrainian authorities said.
"We are fighting. We are not ceasing to defend our motherland," Mariupol Mayor Vadym Boichenko said live on Ukrainian TV.
Moscow said on Wednesday it had captured Kherson, a provincial capital of around a quarter of a million people on the southern front, but Ukraine disputed the claim.
The regional governor had said overnight that it was surrounded, under fire, and Russian troops were looting shops and pharmacies.
On Wednesday an adviser to Mr Zelenskyy said street fighting was going on in the port, which sits at the Dnieper river's exit into the Black Sea.
"The city has not fallen, our side continues to defend," the adviser, Oleksiy Arestovych, said.
Ukrainian Health Minister Viktor Lyashko said Russian forces had killed a paediatric anaesthesiologist, firing at her car as she was driving her wounded nephew to hospital from the village of Kukhari, in the Kyiv region.
Ukraine's defence ministry said a total of 16 guided missiles had been fired in less than an hour on Monday at residential areas of Kharkiv from a strategic bomber flying over Russia's Belgorod region.
"High-rise buildings, schools, kindergartens and other infrastructure of the city were destroyed," the ministry said on its Facebook page.
"Unfortunately, in the current situation, it is extremely difficult for the Air Force to cover the sky in this region, because part of the country's air defence system was destroyed by Russian ballistic and cruise missile strikes."
Reuters said it was not able to confirm any of the incidents.
Video posted to social media showed a police building in Kharkiv had also been hit by a missile attack.
Mr Zelenskyy decried Russia's escalation of attacks on crowded urban areas as a blatant campaign of terror.
"Nobody will forgive. Nobody will forget," he vowed after Tuesday's bloodshed.
Russia ready for new talks
As the fighting raged, Kremlin spokesman Dmitry Peskov said Russia would be ready to resume talks.
It came a day after Mr Zelenskyy said Russia should stop bombing first.
The first talks between Russia and Ukraine since the invasion were held on Monday, but ended with only an agreement to talk again.
Mr Peskov added that Moscow needed to formulate a harsh, thought-out and clear response against measures imposed on Western countries to undermine the Russian economy.
And a top Kremlin official warned that the West's "economic war" against Russia could turn into a "real one".
Russian Foreign Minister Sergei Lavrov ramped up the rhetoric again on Wednesday, saying if a third world war were to take place, it would involve nuclear weapons and be destructive, the RIA news agency reported.
Ukraine forces say Russia's will to fight is fading
Facing emboldened Ukrainian troops bolstered by citizen soldiers, Russia has failed to capture a single city since its full-scale invasion began nearly a week ago.
A statement from Ukraine's military, posted on its Facebook page, said Russian forces were launching missiles at infrastructure because of failures in their advance.
The statement said it had repelled several advances of Russian forces in multiple cities around the country and that Russia's will to fight was fading.
"Unsuccessful in advancing its forces, the enemy insidiously continues to launch missile and bomb strikes on critical infrastructure in order to intimidate the civilian population, which is courageously side by side with the Armed Forces of Ukraine," it said.
Western analysts said Russia had fallen back on tactics which call for devastating bombardments of built-up areas before troops enter them.
People flee Kyiv as Russian forces advance
Hundreds of thousands of Ukrainians have fled the fighting as a miles-long Russian military convoy north of Kyiv advances toward the city.
The were reports that the 64-kilometre-long convoy was slowing, but had still managed to move within 15km of the capital by Wednesday.
Roughly 660,000 people have fled Ukraine, and countless others have taken shelter underground.
The death toll was less clear, with neither Russia nor Ukraine releasing the number of troops lost.
The UN human rights office said it had recorded 136 civilian deaths, but the actual toll would be far higher.
One senior Western intelligence official estimated that 5,000 Russian soldiers had been captured or killed in the biggest ground war in Europe since World War II.
Mr Zelenskyy said on Wednesday that the number of Russian deaths was closer to 6,000.
Russian President Vladimir Putin has drawn global condemnation and sanctions that have sent the rouble to historic lows and forced Russians to queue outside banks for their savings.
Mr Putin ordered the "special military operation" last Thursday in a bid to disarm Ukraine, capture the "neo-Nazis" he said were running the country and crush its hopes of closer ties to the West.
Ukraine, which is not a member of NATO, has called on the US-led military alliance to implement a no-fly zone — a request rejected by Washington, which fears stoking a direct conflict between the world's two biggest nuclear powers.
Washington and its allies have instead sent weapons to Kyiv, and Treasury Secretary Janet Yellen said the US had agreed with partners to convene a task force "to freeze and seize the assets of key Russian elites".
The move "will inflict financial pain on the powerful individuals surrounding Putin and make clear that no one is beyond our collective reach," Ms Yellen said.
US President Joe Biden used his first State of the Union address to highlight the resolve of a reinvigorated Western alliance that has worked to rearm the Ukrainian military and adopt tough sanctions, saying it had left Russian President Vladimir Putin "isolated in the world more than he has ever been".
"Throughout our history we've learned this lesson — when dictators do not pay a price for their aggression, they cause more chaos," Mr Biden said.
"They keep moving. And the costs and threats to America and the world keep rising."
The United Nations General Assembly also looked set to censure Russia over Ukraine invasion, a move aimed to diplomatically isolate Russia at the world body.
By Tuesday evening, nearly half the 193-member General Assembly had signed on as co-sponsors of a draft resolution ahead of a vote on Wednesday, diplomats said.
ABC/Reuters
