Russia's recent missile strikes in Ukraine that killed dozens of civilians show Russian President Vladimir Putin is "mocking" President Donald Trump, Poland's foreign minister Radosław Sikorski said.

U.S. President Donald Trump's special envoy Steve Witkoff flew to Russia on Friday for talks with President Vladimir Putin about the search for a peace deal on Ukraine, the Kremlin said, saying the two men might also discuss a Trump-Putin meeting.

The Trump administration says it will soon be clear if Russia's Vladimir Putin really wants a peace deal in Ukraine, as France and Britain accuse him of playing for time.