US Secretary of State Antony Blinken said the risk of Russian military action in Ukraine was high enough to justify the departure of a large number of US embassy staff in Kyiv.

"We have ordered the departure of most of the Americans who are still at the embassy in Kyiv. The risk of Russian military action is high enough and the threat is close enough, so it is the right thing to do," Blinken said, adding: "The diplomatic path still remains open. Moscow's can very easy show it wants to go down this path- by reducing tensions not escalating them."