Russia launched an air strike on Kiev overnight, Reuters reported, citing a statement by the city's mayor, Vitali Klitschko.
Ukrainian air defenses repelled the attack, he said.
Earlier last night, Ukrainian port authorities said on "Facebook" that at least four people had been killed after a Russian missile strike hit a grain ship in the Black Sea port city of Odessa, but later deleted their message.
According to the statement, the ship "MJ Pinar" was hit while it was loading grain for export.