Russia launched one of its heaviest overnight assaults on Ukraine in recent months, firing hundreds of drones and missiles across multiple regions and killing at least four people in the capital, Kyiv, Ukrainian authorities said Sunday.

The barrage, which lasted for about 12 hours, struck residential areas and civilian infrastructure, including a cardiology center and a kindergarten. A 12-year-old girl was among the victims, and more than 40 others were injured in Zaporizhzhia, Odesa, Sumy, Cherkasy, and Mykolaiv regions. Officials warned the toll could rise as rescue operations continued.

President Volodymyr Zelensky accused Moscow of deliberately prolonging the war to benefit from energy revenues.

“Moscow wants to continue fighting and killing and deserves only the harshest pressure from the world,” he said. He vowed that Ukraine would target Russia’s ability to finance its military campaign and push it toward diplomacy.

Videos shared by Zelensky showed residential buildings engulfed in flames as firefighters battled through the night to rescue trapped residents.

Ukraine’s General Staff reported that Russia fired 643 drones and missiles, including glide bombs, across eastern, central, and southern parts of the country. The attacks followed Moscow’s warning to NATO against taking tougher action over what the alliance has described as repeated Russian airspace violations.

Poland scrambled fighter jets and raised its air defense alert in response to the strikes. Warsaw’s military said on X that the move was precautionary amid the heightened regional tension. Several European nations have recently accused Russia of sending drones and fighter jets into their airspace, which NATO has described as deliberate provocations. Moscow has denied responsibility.

Speaking at the UN General Assembly in New York, Russian Foreign Minister Sergei Lavrov warned that any attack on Russia would trigger “a decisive response.” He also cautioned that any country that shoots down Russian objects within its airspace would “very much regret it.”

Ukraine, meanwhile, received a US-made Patriot air defense system from Israel, with two more expected soon. Zelensky returned from New York, where he addressed the UN and held security talks. Israel’s stance in the conflict has shifted as its relations with Moscow have cooled over Russia’s growing ties with Iran and criticism of Israel’s actions in Gaza.

US and Ukrainian officials are scheduled to meet in the coming weeks to discuss a major arms purchase. Kyiv has submitted a list of weapons it wants to acquire as part of a plan to buy $90 billion worth of arms from Washington, Zelensky said.

Separately, both Kyiv and Moscow confirmed that the Russian-occupied Zaporizhzhia nuclear power plant, Europe’s largest, had been disconnected from the grid for four days, renewing fears of a potential nuclear incident.

The latest strikes come as the war nears its fourth year, with diplomatic efforts largely stalled and Russia signaling no intention of slowing its offensive.