Ukrainian President Volodymyr Zelensky says Russia made a “conscious choice” by launching a major attack on his country’s energy infrastructure on Christmas Day.
The Ukrainian air force said it had detected 184 missiles and drones, but many were shot down or missed their targets.
It said there had been casualties from the strikes, but did not provide figures.
Moscow confirmed the attack and said the objective had been achieved.
The attack led to power outages across the country, including in the capital Kiev, where some residents took shelter in metro stations.
The Russian defense confirmed that its forces had carried out a “massive attack” on “critical” energy facilities in Ukraine.
It added that the attack had been a success and all targets had been hit.
This was the thirteenth major attack on Ukraine’s energy sector this year, according to the country’s largest private energy company, DTEK.
In September, President Zelensky said that 80% of Ukraine’s energy infrastructure had been destroyed by Russian bombs.
Commenting on Wednesday’s attacks, Zelenskiy said the timing of the attacks was a “deliberate choice.”
He called them “inhumane” and said work was being done to restore power as quickly as possible.
“Russian evil will not break Ukraine or distort Christmas,” he added.
This is the second time that Ukraine celebrates Christmas Day on December 25. Traditionally it followed the Julian calendar, like Russia, where Christmas falls on January 7.
In the northeastern city of Kharkiv – Ukraine’s second largest – the attack left half a million people without water, electricity or heating in bitterly cold temperatures, the regional governor said.
Ukrainians across the country woke to air raid sirens and were told to take shelter as the morning attacks unfolded.
Kiev residents sheltered in metro stations, with one local telling Reuters she felt angry and scared.
“Of course I want to be home and celebrate, but we had to take shelter because it’s scary to stay at home,” said Sofiaa Lytvynenko.
Another Kiev resident, Oleksandra, said that despite the attack, “Christmas has not been canceled.”
She told Reuters she planned to enjoy traditional Ukrainian food and drinks with family and friends after it is safe to leave the shelter.
Ukraine’s state energy company Ukrenergo warned Ukrainians that the power outages could last at least until the end of the day.
It has imposed usage restrictions while it tries to restore service.
Meanwhile, Ukrainian Foreign Minister Andrii Sybiha described the strikes as “Christmas terror”.
He said a Russian missile passed through Moldovan and Romanian airspace “which was a reminder that Russia is not only threatening Ukraine.”
Moldovan President Maia Sandu condemned the attack and confirmed that a missile had been detected in the country’s airspace.
Romania said it had not detected a missile in its airspace.
Elsewhere, four people were killed and five others injured by Ukrainian shelling in Russia’s Kursk region, according to the region’s acting governor.