Ukrainian President Volodymyr Zelensky on Wednesday denounced an "inhumane" attack from Russia, which launched dozens of missiles and drones on his war-torn country's energy grid on Christmas Day.

The country woke up at 5:30 a.m. to an air raid alarm, shortly followed by air force reports that Russia had launched Kalibr cruise missiles from the Black Sea.

"Putin deliberately chose Christmas to attack. What could be more inhumane? More than 70 missiles, including ballistic missiles, and more than a hundred attack drones. The target is our energy system," Zelensky said.

This was the 13th large-scale strike on Ukraine's energy system this year, the latest in Russia's campaign targeting the power grid during winter.

The air force shot down over 50 missiles, Zelensky said.

"Unfortunately, there are some hits. As of now, there are blackouts in several regions," he said.

Engineers were working to repair the system, but Ukraine's DTEK energy company said the attack severely damaged equipment of thermal power plants, and regional officials reported power cuts.

"Christmas morning has once again shown that nothing is sacred for the aggressor country," said Svitlana Onyshchuk, the head of the Ivano-Frankivsk region.

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She said part of the region was without electricity "at a time when we celebrate one of the greatest religious holidays -- the bright Christmas."

Ukraine is officially celebrating Christmas on December 25 for a second year.

The government last year changed the date from January 7, when most Orthodox believers celebrate, as a snub to Russia.

The Christmas Day attack targeted central Dnipropetrovsk, whose governor Sergiy Lysak said Russia was "trying to destroy the region's power system."

'WON'T RUIN CHRISTMAS'

Lysak said rescue operations had been completed on the site of a strike on Kryvyi Rig, which killed one person and wounded 17 others the day before.

Ukraine's second biggest city of Kharkiv on Wednesday also faced renewed attacks that wounded six people, governor Oleg Synegubov said.

Russian forces have bombarded Kharkiv almost daily for the past two years.

The governor also said authorities had evacuated 46 people from the area of Borivske and Kupiansk.

Moscow's forces are aiming to recapture the town of Kupiansk, which was occupied in the first year of the war.

Ukraine recaptured it in September 2022 as part of a lightning offensive that saw its forces regain large swathes of the Kharkiv region.

Outmanned Ukrainian troops are on the back foot across the front line in the Kharkiv and Donetsk region further south, ceding ground to better-equipped Russian troops.

Russian attacks killed one resident of the Donetsk region the previous day, governor Vadym Filashkin said.

Both sides are scrambling to gain an upper hand ahead of the inauguration of US president-elect Donald Trump, who boasted he would quickly end the war, raising fears that Washington may force Kyiv into a deal on Moscow's terms.

Ukraine has been urging allies to send more aid to fend off aerial strikes and push back troops on the ground.

"I am grateful to everyone who is working for the country, who is on combat duty, who is protecting our sky," Zelensky said.

"Russian evil will not break Ukraine and will not ruin Christmas," Zelensky said.

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