KYIV, Ukraine, May 25, 2025 (BSS/AFP) - Kyiv came under attack from more than a dozen Russian drones early Sunday, authorities in the Ukrainian capital said as they warned of a missile threat.

AFP journalists heard explosions and locals were urged to seek shelter, as the city came under fire from the sky for the second night running.

On Saturday, Ukraine's air force said Russia launched 14 ballistic missiles and 250 attack drones overnight, adding that it downed six missiles and 245 drones.

The head of Kyiv city's military administration Tymur Tkachenko said "more than a dozen enemy drones" were in airspace around the capital early Sunday.

"New ones are also approaching. Some of the drones over Kyiv and the surrounding area have already been dealt with. But the new ones are still entering the capital," he wrote on Telegram.

"The night will not be easy. There is a threat of the enemy using a large number of drones and missiles from strategic aircraft."

Debris fell on one five-storey residential building, he added.

Kyiv mayor Vitali Klitschko said the city was "under attack" but "air defences are operating", telling citizens: "Stay in shelters!"

The successive overnight attacks come even as Russia and Ukraine pursue the biggest prisoner swap since the start of Moscow's full-scale invasion in February 2022.

Ukraine's President Volodymyr Zelensky said on Saturday evening the attacks indicated Moscow was "prolonging the war" and repeated his call for ramped-up sanctions.

On Saturday, 307 Russian prisoners of war were exchanged for the same number of Ukrainian soldiers, according to announcements in Kyiv and Moscow.

The first part of the large-scale swap involved 270 soldiers and civilians from each side on Friday.