US President Joe Biden has condemned Vladimir Putin's "reckless" nuclear threats and accused him of "shamelessly violating the core tenets" of the United Nations charter.
In an address to the United Nations General Assembly in New York, Mr Biden said the US and its allies would continue to stand in solidarity against Russia.
The US President said it was a "brutal needless war, a war chosen by one man, to be very blunt."
He said Mr Putin had made "overt nuclear threats against Ukraine in reckless disregard for [his] responsibilities."
Mr Biden’s speech had to be re-written after the Russian leader threatened a nuclear conflict with the West and announced that 300,000 reserve troops would be drafted into the army.
Mr Putin said he was “not bluffing” on nuclear weapons and warned Russia would use all the means at its disposal to protect territory it plans to annex in Ukraine through sham referendums.
Many flights out of Russia have sold out, with fears that men of fighting age will soon be barred from leaving the country.
NATO chief calls Putin's nuclear threat a 'dangerous' escalation
Vladimir Putin's thinly veiled threat to use nuclear weapons after Russian setbacks in Ukraine was "dangerous and reckless rhetoric," NATO's secretary general has said, adding that the only way to end the war was to prove Moscow will not win on the battlefield.
Jens Stoltenberg also told Reuters in an interview that Putin's announcement of Russia's first military mobilisation since World War Two would escalate the conflict and cost more lives. But, the NATO chief added, it also represented evidence that Putin had made a "big mistake" with Russia's decision to invade its neighbour on Feb. 24.
Mr Stoltenberg said NATO will stay calm and "not engage in that same kind of reckless and dangerous nuclear rhetoric as President Putin."
"The only way to end this war is to prove that President Putin will not win on the battlefield. When he realises that, he has to sit down and negotiate a reasonable agreement with Ukraine," Mr Stoltenberg said.
Russia releases prisoners of war Russia has released 10 prisoners of war captured in Ukraine following a mediation by Saudi Crown Prince Mohammed bin Salman, a Saudi official has said.The list includes American, British, Swedish, Croatian and Moroccan nationals, the official said, adding that a plane carrying the prisoners landed in the kingdom.
Today's Ukraine podcast
Today, we discuss Vladimir Putin’s extraordinary speech this morning, ordering a partial mobilisation of 300,000 Russian reservists and claiming that he is not bluffing on the use of nuclear weapons. What is his strategy? And how should the West, and the wider world, respond?
Listen to Francis Dearnley, Dom Nicholls, Roland Oliphant and Nataliya Vasilyeva here.