Ukrainian Energy Minister German Galushchenko said on Saturday that the coming days would be "difficult" on the energy front after a massive missile attack by Russia hit critical infrastructure in several regions.
"Due to the shelling in the majority of the regions, emergency (power) cut-offs are being introduced. The coming days will be difficult," he wrote on Facebook.
Galushchenko said energy infrastructure in six Ukrainian regions was damaged after the attacks.
DTEK, Ukraine's largest private energy company, said two of its thermal power stations were hit in Saturday's strikes. One station stopped producing electricity.
Government officials have previously said that about 40% of Ukraine's energy system has been damaged following three months of missile and drone attacks on the country's energy infrastructure.
Kyrylo Tymoshenko, deputy head of the president's office, said that more than 300,000 generators were delivered to Ukraine in December as the country battles to survive the cold winter months despite the damage to power infrastructure.
(Reporting by Olena Harmash; Writing by Tom Balmforth; Editing by Mark Potter and Frances Kerry)
