Russia unleashed one of its biggest aerial assaults in months on Sunday, pounding Kyiv and several other Ukrainian cities in a 12-hour drone and missile barrage that killed at least four people in the capital and injured dozens more.

“A massive Russian attack on Ukraine lasted for more than 12 hours. Savage strikes, a deliberate, targeted terror against ordinary cities,” President Volodymyr Zelenskyy said.

Nearly 600 drones and dozens of missiles were launched overnight, with Kyiv suffering the heaviest bombardment since last month’s strike that left 21 dead. Poland scrambled fighter jets to protect its airspace amid the onslaught, as NATO accused Moscow of repeated violations in recent weeks.

Ukraine’s foreign ministry said civilian infrastructure was hit, including residential buildings, a cardiology centre, and a kindergarten. Casualties were also reported in Zaporizhzhia, Odesa, Sumy, Cherkasy, and Mykolaiv. In Zaporizhzhia alone, governor Ivan Fedorov reported at least four strikes and 42 people injured. The region also hosts Europe’s largest nuclear power plant, under Russian control.

Diplomatic efforts to halt the war remain stalled, with Moscow insisting it will press on with the offensive launched in February 2022. “Moscow wants to continue fighting and killing and deserves only the harshest pressure from the world,” Zelenskyy said after speaking with NATO chief Mark Rutte and leaders of Finland and Norway.

Russia claimed its strikes targeted only military sites, while denying accusations of violating NATO airspace.