US President Joe Biden and UK's PM Liz Truss agree on continued support for Ukraine

British Prime Minister Liz Truss and U.S. President Joe Biden agreed on Wednesday that Russian President Vladimir Putin's actions highlight the need for allies to continue their economic and military support to Ukraine, Truss's office said.

Putin ordered Russia's first wartime mobilisation since World War Two on Wednesday during a televised address in which he also announced moves to annex swaths of Ukrainian territory and threatened to use nuclear weapons to defend Russia.

"The leaders condemned Putin's recent belligerent statements on Ukraine," a spokesperson for Truss, who took office just over two weeks ago, said following the pair's first in-person meeting.

"They agreed his actions highlight the need for allies to continue their economic and military support to Ukraine."

The spokesperson said that during the meeting, which took place at the UN General Assembly in New York, the leaders had also stressed the need to "end over-reliance on authoritarian states in terms of our energy, technology and manufacturing supply chains".

"They agreed to redouble bilateral efforts to reduce energy dependence on Russia and to increase the amount of renewable and other forms of energy flowing from democratic states," the spokesperson added.