The Kremlin said on Monday it could neither confirm nor deny whether or not Russian President Vladimir Putin had spoken to U.S. President Donald Trump by phone about finding a way to stop the war in Ukraine.

Mystery surrounds the first direct contact between the leaders of the two largest nuclear powers since Russian began its full-scale war in Ukraine in February 2022, with both Washington and Moscow offering partial answers and hints.

Trump, speaking to reporters aboard Air Force One on Sunday, said he believed the United States was making progress, but declined to provide details about any communications with Putin.