Eight Russian missiles hit Ukraine's largest hydroelectric power plant in the early hours of Friday, causing "significant damage" to the facility, the office of Ukraine's Prosecutor General said.
Moscow launched a barrage of missiles and drones at Ukrainian energy facilities overnight, one of the largest aerial attacks of the two-year war.
The Dnipro Hydroelectric Station "was hit eight times," said Yury Belousov, head of the Prosecutor General's war crimes department on Ukrainian TV.
"The facility is really out of commission. The damage is very significant," he added.
The power station straddles the vast Dnipro river in the southeastern city of Zaporizhzhia, close to the front lines.
Russia partially controls the wider Zaporizhzhia region, which it claims to have annexed.
Photos on social media showed a fire raging on the station's dam in the early hours.
A trolleybus driving across the dam's roadway had been hit in the missile attack and its 62-year-old driver killed, Zaporizhzhia Governor Ivan Fedorov said.
The hydro plant is about 60 kilometres (37 miles) upstream from the Zaporizhzhia nuclear power plant, which Russian forces seized at the start of the war.
Ukraine's energy ministry said the situation at the hydro plant was "under control" following the strikes.
"There is no threat of a dam breach. However, the facility was damaged," it said in a statement on Friday morning.