Science secretary Peter Kyle has warned that claims Russia is planning a “significant air attack” on the US embassy in Ukraine should be “taken very very seriously”.

US diplomats posted about a potential security alert on social media on Wednesday morning, saying they had received “specific information” of a strike against them and so would be closing the Kyiv embassy.

The post on X also recommended US citizens in Ukraine should be “prepared to immediately shelter in the event an air alert is announced”.

It comes after reports that the States had finally given Ukraine permission to use its long-range missiles to target sites within Russia.

Responding to concerns over the attack on the US embassy, Kyle told Sky News this morning: “I’m not surprised, because we’ve seen escalation from Vladimir Putin when he has every opportunity after a 1,000 days [of war] to de-escalate, but it is a shocking escalation on behalf of Vladimir Putin and something we should take very very seriously.”

But the cabinet minister refused to disclose any plans from the Ministry of Defence over potentially closing the UK’s embassy in Kyiv.

He said: “We will do whatever it takes to keep our people safe but it will be based on the evidence and intelligence we have at any moment.”

“As you can imagine, every day we are assessing all of the evidence that intelligence brings us, our relationship with the US, Kyiv, is very very tight,” he said, later adding: “Our diplomats are working very well in Ukraine, I have absolute fulsome praise for all the work they do day in day out to support Ukraine.”

Kyle also refused to be drawn on whether the UK would follow the US and allow Ukraine to use its own long-range missiles to attack Russia.

He said: “I can’t give operational information at the moment on these sort of things because at the moment, it would benefit Vladimir Putin more than anyone else.”

But the minister did call on Putin to de-escalate, saying: “To end this war, it is in his power to end it today.”

Since the US allegedly granted Ukraine permission to use its long-range weapons, Putin has only made it easier for Russia to launch its own nuclear weapon, by lowering the threshold to which it can use its deadly arsenal.