Amid a renewed U.S.-led diplomatic drive to end the Ukraine war, U.S. special envoy Steve Witkoff met with Russia's Vladimir Putin for a sixth time.

Vladimir Putin hosted US negotiators at the Kremlin on Tuesday for five hours of talks aimed at ending the war in Ukraine, which a Russian official said had been "productive".

Ukrainian President Volodymyr Zelensky described the talks as "constructive", but said there are "some tough issues that still have to be worked through".