Russia carried out a “massive” missile attack on Ukrainian energy infrastructure overnight into Wednesday, according to local authorities, in the biggest aerial onslaught by Russian forces for weeks.

Russia used 76 air attack weapons in the assault, including 55 missiles and 21 drones launched from Russia and Russian-controlled areas, according to Ukrainian Air Force Commander Mykola Oleshchuk. At least 59 weapons were destroyed overnight, he added.

The attacks targeted power generation and transmission facilities in Ukraine’s Poltava, Kirovohrad, Zaporizhzhia, Lviv, Ivano-Frankivsk, and Vinnytsia regions, the country’s Energy Minister Herman Halushchenko posted on Telegram.

“The enemy wants to deprive us of the ability to generate and transmit electricity in sufficient quantities. Saving electricity is a contribution of each of us to the victory,” Halushchenko said.

At least three people were injured, including a woman and a man with multiple limb injuries and shrapnel wounds taken to the hospital in the Kyiv region, and an 8-year-old child in the Kirovohrad region, local authorities said.

Moscow has stepped up efforts to paralyze Ukraine’s energy system in the past month, as Kyiv’s troops struggle to hold positions on key frontlines, particularly in the east.

The five-month wait before US Congress approved $61 billion in military aid to Kyiv may have caused lasting damage that will be felt on the frontlines for months to come.