Ukrainian President Volodymyr Zelensky on Sunday called for a “unilateral ceasefire in the skies” after Russia launched its latest aerial attack on the energy infrastructure in Ukraine, killing at least five people and wounding 10.

The assault targeted nine regions and left thousands of Ukrainians without electricity as the war rages on. Among the regions targeted was Lviv, which lies about 40 miles east of the Polish border. Ukrainian officials said it was one of the largest attacks on Lviv since the war began.