Moscow said on Monday it would provide corridors for residents of Ukraine's two main cities to flee to Russia and Belarus, a move Ukraine called an immoral stunt to exploit the suffering of civilians under Russian bombardment.
Russian and Ukrainian delegations assembled for a third round of talks in Belarus, both sides said. Two previous rounds yielded little beyond pledges to open routes for humanitarian access that have yet to be successfully implemented.
"In a few minutes, we will start talking to representatives of a country that seriously believes large-scale violence against civilians is an argument," Ukrainian negotiator Mykhailo Podolyak said on Twitter. "Prove that this is not the case."
Russia's announcement of "humanitarian corridors" came after two days of failed ceasefires to allow civilians to escape the besieged city of Mariupol, where hundreds of thousands are trapped without food and water, under relentless bombardment.
A corridor from Kyiv would lead to Russia's ally Belarus, while civilians from Kharkiv, Ukraine's second-biggest city, would be directed to Russia, report Reuters citing some maps published by the RIA news agency.
"Attempts by the Ukrainian side to deceive Russia and the whole civilised world ... are useless this time," the ministry said.
A spokesperson for Ukrainian President Volodymyr Zelensky called the move "completely immoral" saying Russia was trying to "use people's suffering to create a television picture".
"They are citizens of Ukraine, they should have the right to evacuate to the territory of Ukraine," the spokesperson told Reuters.
More than 1.7 million Ukrainians fleeing Russia's invasion have so far crossed into Central Europe, the United Nations refugee agency said on Monday, as thousands more streamed in that direction.
Sweeping sanctions have subjected Russia to isolation from global commerce never before visited on such a large economy. Global share prices plunged on Monday after Washington said it was considering extending sanctions to Russia's energy exports, until now carved out from trade bans.
Russia is the world's biggest exporter of oil and gas. Brent crude prices briefly spiked above $139 a barrel on Monday, the closest they have come in 14 years to the all-time high of $147. Investment banks say prices could approach $200 this year if Russian supply evaporates, with dire consequences for the global economy. Russia and Ukraine are also both among the world's main exporters of food and industrial metals.
Russia denies deliberately targeting civilians. It calls the campaign it launched on Feb. 24 a "special military operation" to disarm Ukraine and remove leaders it describes as neo-Nazis. Ukraine and its Western allies call this a transparent pretext for an invasion to conquer a nation of 44 million people.
The general staff of Ukraine's armed forces said Russian forces were "beginning to accumulate resources for the storming of Kyiv", a city of more than 3 million, after days of slow progress in their main advance south from Belarus.