Russia planned to open humanitarian corridors in Ukraine Tuesday for civilians to flee besieged cities, but Kyiv insisted the move was a publicity stunt and people would not be able to escape.
Moscow's offer to evacuate residents was condemned because most of the routes led into Russia or its ally Belarus, and as the invading forces maintained a devastating shelling campaign.
The Ukrainian military said Tuesday, nearly two weeks into the war, that Russia was ramping up its troops and equipment around the main conflict zones.
The invasion has sparked the biggest war in Europe and the continent's largest refugee crisis since World War II, while the West has responded with sanctions on Russia that have reverberated around the global economy.
Russia's defence ministry said it would open the "humanitarian corridors" from 0700 GMT Tuesday, subject to Ukraine's approval, listing routes from the capital Kyiv as well as the cities of Mariupol, Kharkiv and Sumy -- all of which have been under heavy attack.
Ukraine did not initially respond to the offer.
But Ukrainian President Volodymyr Zelenskyy accused Russia of reneging on previous escape route agreements, and trying to stop people such as by planting explosives on roads.
"There was an agreement on humanitarian corridors. Did that work? Russian tanks worked in its place, Russian Grads (multiple rocket launchers), Russian mines," Zelenskyy said in a video posted on Telegram.
Accusing Moscow of "cynicism", Zelenskyy also said Russian troops destroyed buses that were due to evacuate civilians from the combat zones.
"They ensure that a small corridor to the occupied territory is open for a few dozen people. Not so much towards Russia as towards the propagandists, directly towards the television cameras," he said.
French President Emmanuel Macron also condemned the Russian plan.
"All this is not serious, it is moral and political cynicism, which I find intolerable," Macron told French broadcaster LCI.
"I do not know many Ukrainians who want to go to Russia," he added, saying full ceasefires to protect civilians were needed rather than corridors.
Addressing the Security Council, the UN's top humanitarian official Martin Griffiths also said civilians must be allowed to leave in the direction they wish.
At least 406 civilians have died since the start of Russia's assault on its ex-Soviet neighbour, according to the UN, although it believes the real figures to be "considerably higher".
Ukrainian forces said Tuesday they had repulsed a Russian attack on Izium city in the Kharkiv region, and outgunned troops have been trying to hold back a Russian push up from the east and south in an attempt to encircle Kyiv.
Russian forces "suffered losses and retreated" in Izium after they "reigned terror in the city by bombing civilian premises and infrastructure," the military said.
AFP journalists witnessed thousands of civilians on Monday fleeing fighting via an unofficial escape route from Irpin, a suburb west of Kyiv, towards the capital.
Children and the elderly were carried on carpets used as stretchers on the route, which leads over the makeshift bridge and along a single path secured by the army and volunteers.
Desperate people abandoned pushchairs and heavy suitcases to cram on buses out of the war zone.
"We had no light at home, no water, we just sat in the basement," Inna Scherbanyova, 54, an economist from Irpin, told AFP.
"Explosions were constantly going off... Near our house there are cars, there were dead people in one of them... very scary."
Refugees trying to escape the city using agreed escape routes were left stranded as the road they were directed towards was mined, the ICRC said on Monday.
One Ukrainian paratrooper told of "hand-to-hand" combat in Irpin, saying "we are trying to push (Russian soldiers) out, but I don't know if we'll be fully able to do it".
An international legion of volunteers has descended on Ukraine to fight the Russians.
But the Pentagon said Monday that Moscow was on a recruiting mission for its own foreign fighters -- Syrians who fought for President Bashar al-Assad.
"We do believe that the accounts of them -- the Russians -- seeking Syrian fighters to augment their forces in Ukraine, we believe there's truth to that," Pentagon spokesman John Kirby told reporters.
Also read: Despite repeated urgings, no safe corridor for students stranded in Sumy: India tells UNSC
Russian President Vladimir Putin on Monday said he will not send conscripts or reservists to fight in the conflict.
Zelenskyy has recalled all servicemen working abroad to fight the invading forces, according to the Ukrainian parliament.
He again vowed to remain in place as Russian forces near the capital.
"I am staying in Kyiv. Not hiding. And I'm not afraid of anyone," he said in a video late Monday.
He said his government will do "as much as it takes to win this war!"
The World Bank on Monday approved an additional $489-million package in support for Ukraine, to be made available immediately and dubbed "Financing of Recovery from Economic Emergency in Ukraine," or "FREE Ukraine."
It came as Zelenskyy renewed calls for the West to boycott Russian exports, particularly oil, and to impose a no-fly zone to stop the carnage.
NATO countries have so far rebuffed Kyiv's demand for a no-fly zone, fearing a widening war against nuclear-armed Russia.
Western allies have instead imposed unprecedented sanctions against businesses, banks and billionaires in a bid to pressure Moscow to halt its assault.
But the leaders of Germany, Britain and the Netherlands warned Monday against a ban on Russian oil, saying it could put Europe's energy security at risk.
US President Joe Biden's spokeswoman said no decision had been taken, while Russian Deputy Prime Minister Alexander Novak warned any oil ban would have "catastrophic consequences" on prices that have already headed towards a 2008 record high.
Putin has equated sanctions with a declaration of war and put nuclear forces on alert, pledging the "neutralisation" of Ukraine "either through negotiation or through war".
Despite harsh punishments for those voicing dissent, protests in Russia against the Ukraine invasion have continued, with more than 10,000 people arrested since it began.