Ukraine said it hit a drone command unit in the Kursk region, amid reports of fresh attempts to cross into Russia. Sunday's attack on the unit was located near the Russian village of Tyotkino, according to the Ukrainian general staff.

Russian air defences downed a swarm of Ukrainian drones targeting Moscow for the second consecutive night, forcing airport closures but causing no reported casualties.

Dmitry Medvedev, deputy chairman of Russia's Security Council, said on Saturday that nobody could guarantee that the Ukrainian capital of Kyiv would survive to see May 10 if Ukraine attacked Moscow during World War Two victory celebrations on May 9.