Ukraine has said Russia launched a "massive" overnight attack on energy infrastructure in the country's west and south.
"Equipment at (operator) Ukrenergo facilities in Zaporizhzhia and Lviv regions was damaged," the energy ministry said on Saturday, adding that two employees were wounded and hospitalised in Zaporizhzhia.
It said this was "the eighth massive, combined attack on energy infrastructure facilities" in the past three months.
More than two years into Russia's attacks on Ukraine, targeted missile and drone strikes have crippled Ukraine's electricity generation capacity and forced Kiev to impose blackouts and import supplies from the European Union.
Ukrainian authorities on Thursday said energy infrastructure, including a power station, had been damaged in a major overnight attack which left seven employees wounded.
DTEK, the largest private energy company in Ukraine, said the strikes caused "serious damage" at one of its plants.
Russian attacks have destroyed half of Ukraine's energy capacity, according to President Volodymyr Zelenskyy.
Zelenskyy said this week that all hospitals and schools in Ukraine must be equipped with solar panels "as soon as possible".
"We are doing everything to ensure that Russian attempts to blackmail us on heat and electricity fail," he said Thursday.
Air-defence systems
DTEK chief executive Maxim Timchenko warned that Ukraine "faces a serious crisis this winter" if the country's Western allies do not provide military aid to defend the energy network.
Zelenskyy has repeatedly urged Ukraine's allies to send more air defence systems to protect the country's vital infrastructure.
US National Security Council spokesman John Kirby said on Thursday that Washington would prioritise deliveries of anti-air missiles to Kiev, ahead of other countries that have placed orders.
Zelenskyy said in a message on X he was "deeply grateful" for the US move.
"These additional air defence capabilities will protect Ukrainian cities and civilians," he wrote.