KYIV -- A fire broke out in Ukraine's government building in the capital following Russian drone attacks, authorities said on Sunday.

According to preliminary information, the blaze was triggered after air defense downed a drone, Kyiv Mayor Vitali Klitschko wrote on Telegram.

"For the first time, a government building, including its roof and upper floors, was damaged," said Prime Minister Yulia Svyrydenko on Telegram, adding, "Rescuers are extinguishing the fire."

The State Service for Emergencies reported that at least two people were killed and 18 others wounded in the strikes. A nine-story apartment building in the Sviatoshynskyi district of Kyiv was partially destroyed in the attacks.

Ukraine's Air Force said on Facebook that Russia launched 818 air assault vehicles overnight, including 805 drones and 13 missiles.