Russia launched an aerial attack targeting several Ukrainian cities overnight into Monday, marking the most significant air attack since the war began, according to Ukrainian leaders.

Ukrainian President Volodymyr Zelensky said the attacks featured more than 120 missiles and more than 100 drones, launched at targets in the Volyn, Lviv, Ivano-Frankivsk, Vinnytsia, Khmelnytskyi, and Ternopil regions. At least four people were killed, according to the Associated Press.