Russia launched one of its largest air strikes on Kyiv in over three years of war and struck a maternity ward in the southern city of Odesa, officials said.

Russia launched 315 drones at Ukraine overnight into Tuesday, in what Ukrainian President Volodymyr Zelensky said was “one of the largest” attacks on the capital Kyiv, with local officials in the southern port city of Odesa also reporting a maternity ward there had been hit.

Kyiv’s success during the June 10 attack demonstrates the growing sophistication of the Ukrainian air defense system—but also the increasing pressure the system is facing against the Russian onslaught.