Russian drones and missiles hit Ukraine's second-largest city, Kharkiv knocking out power during freezing winter weather, while 23 people were wounded in an overnight attack on the southern city of Odesa, officials said.
Two people were injured and two schools damaged in the attack on Kharkiv, Regional Governor Oleh Syniehubov said on the Telegram messaging app.
Pictures on unofficial Telegram channels showed the eastern city, a frequent Russian target 30km from the Russian border, plunged into darkness.
The Ukrainian air force said that Russian troops had launched 165 drones - 135 of them neutralised by air defence units.
"Our energy system came under attack and there was quite serious damage. All crews are at work to eliminate all the negative consequences quickly," Mr Syniehubov said in a video posted on Telegram.
"About 80% of the city of Kharkiv and Kharkiv region is without electricity," he added.
The constant threat of further air raids was complicating repair efforts, he said.
Russia also carried out a "massive" drone attack on the southern city of Odesa overnight, the head of the city's military administration, Serhiy Lysak, said on Telegram.
Regional governor Oleh Kiper said that among the 23 injured, nine people including two children and a pregnant woman had been hospitalised.
People could still be trapped under the rubble, he said.
Dozens of residential buildings, a church, a kindergarten and a high school were damaged in the attack, which caused large fires in several locations, Mr Kiper added.
The city of Odesa and the surrounding region, which houses Ukraine's Black Sea ports, have been frequent targets of Russian attacks in recent weeks.
Energy infrastructure was the main target of a drone attack in the neighbouring Mykolaiv region, the regional governor said, adding that a woman was injured.
In western Ukraine's Lviv region, which borders NATO-member Poland, an infrastructure facility also came under Russian attack, the regional governor said.
