Russia’s nuclear threats ‘totally unacceptable’, says UN chief

The UN secretary general has issued a strongly worded rebuke to Russia for "totally unacceptable" nuclear threats and denounced its plans to annex parts of Ukraine as a "violation of the UN charter and of international law".

António Guterres also said the impact of the conflict could cause a food supply crisis next year. "Simply put the world will run out of food," he said.

Guterres was speaking at the start of a UN security council meeting the day after Vladimir Putin raised the stakes in his invasion of Ukraine, announcing a partial mobilisation and threatening the use of nuclear weapons "if the territorial integrity of our country is threatened". Putin also approved referendums in four Ukrainian regions intended to pave the way for annexation, raising the prospect that he would then deem Ukrainian operations to recapture them as a threat to Russia's "territorial integrity".

The US president, Joe Biden, rejected the nuclear threat as reckless, and Ukraine's backers said they would not be deterred from providing military support.

"The idea of nuclear conflict, once unthinkable, has become a subject of debate. This in itself is totally unacceptable," Guterres said.

"I'm also deeply concerned by reports of plans to organise so-called referenda in areas of Ukraine that are not currently under government control," he said. "Any annexation of a state's territory by another state resulting from a threat or use of force is a violation of the UN charter and of international law."

Russia was widely condemned at Thursday's security council meeting chaired by the French foreign minister, Catherine Colonna.