Russia launched a sweeping drone assault and airstrikes across Ukraine overnight into Sunday, killing at least four people, officials said, after U.S. President Donald Trump cast doubt over Russian President Vladimir Putin’s willingness to end the war.

President Donald Trump said Saturday that he is beginning to question whether Russian President Vladimir Putin wants to end the Russia-Ukraine war, a warning shot to the Russian leader that came just after Trump met with Ukrainian President Volodymyr Zelenskyy in Rome.