Donald Trump joined a teleconference with European leaders including Ukrainian President Volodymyr Zelenskiy on Wednesday, two days before the U.S. leader is due to hold a summit in Alaska with Russia's Vladimir Putin to discuss how to end the war in Ukraine.

German Chancellor Friedrich Merz has said the positions of Ukraine, its European allies and US President Donald Trump are "very much in agreement" ahead of a planned meeting between Trump and Russian President Vladimir Putin in Alaska later this week.