Khodorkovsky, once Russia's richest man, fell foul of Putin in the early 2000s and spent 10 years in prison on fraud charges that human rights groups and Western governments said were politically motivated. He is now based in London.

Russian President Vladimir Putin and U.S. President Donald Trump held their eighth phone conversation on Thursday, said Kremlin aide Yury Ushakov. Ushakov described the Russia-initiated call, which lasted nearly 2.

The Kremlin has welcomed U.S. President Donald Trump’s comments about Russia’s offer to extend the last remaining nuclear arms treaty with the United States, saying it raises hope for keeping the pact alive after it expires in February.

Trump is seeking another diplomatic breakthrough days after brokering a ceasefire deal between Israel and Hamas.

U.S. President Donald Trump and Russia's Vladimir Putin will speak on Thursday, one day before Ukrainian President Volodymyr Zelenskiy visits the White House, Axios reported on Thursday, citing a source with knowledge of the matter.