Air defenses shot down 21 of 28 drones launched by Russia overnight, the Ukrainian Air Force said Sunday. Russia also launched three anti-aircraft missiles against Ukraine.

The Russian Defense Ministry said its defenses intercepted 36 drones over Crimea and one over Krasnodar, part of an emerging pattern of intensified Ukrainian aerial attacks in recent days.

Russia’s Defense Ministry says air defenses shot down 10 Ukrainian air-launched missiles over the Moscow-annexed Crimean Peninsula.

The massive prisoner exchange followed other such deals earlier in the war, which is nearing the 2-year mark.

Air defenses shot down all 10 of the Russian Kinzhal missiles, which can fly at 10 times the speed of sound, out of about 100 of various types that were launched, said Gen. Valerii Zaluzhnyi, Ukraine’s commander-in-chief.

The Ukrainian Air Force said Sunday that it had shot down 21 of 49 drones launched by Russian forces overnight.

The attack, if confirmed, would be one of the deadliest inside Russia since it invaded Ukraine nearly two years ago.

Western officials and analysts recently warned that Russia had limited its cruise missile strikes in recent months in an apparent effort to build up stockpiles for massive strikes during the winter.