Boris Johnson is expected to plead with the US to send more aid to Ukraine after Joe Biden rejected Zelensky's request to send fighter jets.

The former British prime minister is scheduled to speak at a number of Republican events on Tuesday where he is expected to press the issue of aid to Ukraine.

Representative Joe Wilson, a member of the House of Representatives Foreign Affairs Committee said Mr Johnson would speak at a private Republican club in Washington this evening.

Todd Young, the US senator, said Mr Johnson is also scheduled to meet with a group of Republican senators.

On Wednesday the former British prime minister will discuss the need for "Western unity and support for Ukraine and what more can be done against the threat Russia poses" at the Atlantic Council think tank.