Ukraine's intelligence chief has warned that Russia is planning to split the country in two, along Korean lines, as President Volodymyr Zelenskiy urged Nato to share its weapons rather than let them "gather dust".
His plea came after a speech by US president Joe Biden in Warsaw that Russia's Vladimir Putin "cannot remain in power". His apparently off-the-cuff remark infuriated Moscow and has caused irritation elsewhere in Europe, with French president Emmanuel Macron warning against an "escalation of words or actions".
US officials insisted that Washington did not support regime change in Russia and late on Sunday night Mr Biden said he is not seeking Russian leader to be removed from power.
Asked by reporters in Washington on Sunday night whether he was calling for regime change in Moscow following the Russian invasion of Ukraine, Mr Biden replied: "No".
The US government has been trying to walk back ad lib comments made by the president at the end of a 27-minute speech in Warsaw, Poland on Saturday.
“For God’s sake, this man cannot remain in power”, he said .
In his speech, Mr Biden said that Nato would defend “every inch of its territory” and promised to “stand with” Ukraine.
But in a video response on Saturday, the Ukrainian president said equipment his country badly needed was “gathering dust” in Nato depots.
“Who is in charge of the Euro-Atlantic community? Is it really still Moscow, because of intimidation?” Mr Zelenskiy asked.
A spokesman said that, during a Saturday phone call with his Polish counterpart, Andrzej Duda, Mr Zelenskiy said "the price of procrastination with planes is thousands of lives of Ukrainians".
After Mr Biden's speech, which was warmly received in Poland, Ukrainian MP Inna Sovsun tweeted: "I am happy he reassured Poland, but the bombs are exploding in Kyiv, and Kharkiv, not in Warsaw."
On Sunday, Ukrainian interior ministry adviser Vadym Denysenko warned that Russia had begun destroying Ukrainian fuel and food storage centres, meaning the government will have to disperse stocks of both in the near future.
As Russia’s invasion of Ukraine enters its second month, and with no major city captured, Moscow officials have announced a recalibrated campaign to capture the eastern Donbas region, controlled by Russian-backed separatists since 2014.
Local Donbas officials indicated on Sunday they could soon hold a referendum to join Russia, copying the blueprint of Crimea. After it was annexed eight years ago, voters backed joining Russia in a vote not recognised by most countries.
On Sunday, a foreign ministry spokesman in Kyiv dismissed talk of a Donbas referendum. But Ukraine's military intelligence head said such a vote, combined with the military shift, was part of "an attempt to create North and South Korea in Ukraine".
Ukraine’s intelligence chief, Kyrylo Budanov, said Russia’s military options would decline still further when “the season of a total Ukrainian guerrilla safari will soon begin”.
On Saturday evening, after Mr Biden visited a refugee centre in Warsaw, heused an open-air speech to denounce Vladimir Putin as an autocratic “dictator”. Near the end, he said: “For God’s sake, this man cannot remain in power.”
Immediately afterwards, his officials insisted the president was “not discussing Putin’s power in Russia, or regime change”, but his illegitimate efforts to dominate Russia’s neighbours.
US secretary of state Antony Blinken, who accompanied Mr Biden to Warsaw, said the president was arguing that Mr Putin "cannot be empowered to wage war or engage in aggression against Ukraine or anyone else".
Kremlin spokesman Dmitry Peskov warned that "personal insults like this narrow the window of opportunity for our bilateral relations", hours after Russian rockets destroyed a fuel depot in Lviv, 60km from the Polish border.
Richard Haass, president of the US Council on Foreign Relations, said the remark "made a difficult situation more difficult and a dangerous situation more dangerous".