Anthony Blinken, the US secretary of State, is due to hold talks with Sergei Lavrov, Russia’s foreign minister, on Friday in what could be the last chance for a peaceful solution for the crisis.

He was in Berlin on Thursday to confer with his German, British, and French counterparts in Berlin in a last minute diplomatic scramble to maintain Nato unity and avert a conflict.

The diplomatic effort has been accompanied with an increase in military assistance to Ukraine as fears mount an attack is imminent.

A State Department official with Mr Blinken’s delegation in Berlin said the US was “expediting authorised transfers of US-origin equipment from other allies” after Lithuania said it wanted to send some of its American-made weapons to Ukraine.

“European allies have what they need to move forward on additional security assistance (to) Ukraine in the coming days and weeks,” the official said.

Britain began airlifting short-range anti-tank missiles to Ukraine to strengthen its defences against a possible ground attack.

The meeting in Berlin came as Emmanuel Macron, the president of France, was accused of sowing transatlantic divisions by suggesting the European Union countries should “conduct their own dialogue” with Russia.

Mr Macron, who wants the EU to beef up its defences to become less reliant on Nato and the US, said in a speech to the European Parliament that the bloc must make its own offer on Russia’s security demands.

“We should build as Europeans working with other Europeans and with Nato and then propose it for negotiation with Russia,” he said.