Ukrainian drones attacked Moscow for the second consecutive night halting flights at four airports, Russian officials said, as the city prepares to host a major military parade expected to be attended by world leaders including China’s Xi Jinping.

Twice in the last two days, Ukrainian drones have threatened Moscow, but it is unlikely they will disrupt the Kremlin’s showcase Victory Day celebration.

A Ukrainian drone attack forced Moscow to close its airports for several hours, Russian officials said on Tuesday, before President Vladimir Putin will host several leaders to celebrate the 80th anniversary of the defeat of Nazi Germany.