Moscow said its forces attacked so-called military installations in retaliation for attacks on Russian civilian infrastructure.
Kremlin spokesman Dmitry Peskov told reporters on Thursday that Russia would “continue to increase pressure on the Kiev regime to achieve our set goals.”
Ukraine accused Moscow of targeting civilian areas and said it was wrong to equate the actions of the “aggressor and a country defending itself.”
Children were among the “significant number” of victims, said Tymur Tkachenko, the head of Kiev’s military administration.
“The enemy is again targeting residential areas and killing civilians,” he said early Thursday.
According to Kyiv metro authorities, 52,500 people, including 4,500 children, were accommodated in metro stations overnight, which they said was the highest number since “recent years.”
Among the locations hit by the attacks was a high-rise residential building on the city’s left bank in the Darnitskyi district of southeastern Kiev, where two rockets wreaked havoc.
A rocket left a huge crater next to a kindergarten and surrounding buildings were destroyed by fire, their metal balconies bent.
The second rocket landed a few steps away and hit the end of a nine-story apartment block. It collapsed and slid off the building’s facade into a pile of concrete. A local told the BBC that several people were missing and may have taken shelter in the basement.
There are smashed cars, broken windows and a thick layer of gray ash covering everything and everyone.
Rescuers tried to dig through the rubble to reach them as relatives looked on in tears.
Svitlana, who lives next door to the building that was hit, told the BBC she hid in the corridor during the airstrike and heard the explosions.
“It wasn’t scary,” she shrugged, “because I’ve been through it all before.” She then revealed that she had been seriously injured in another Russian attack on another city in which her mother was killed. Two years later, her son was killed fighting for Ukraine.
Oleksiy, whose face was covered in cuts and blood, told the BBC he went outside to smoke after hearing the first rocket, then the second landed and he was hit by flying glass.
“This is not Russia’s retaliation for the Ukrainian attacks,” he said, rejecting Moscow’s explanation for its latest attack. “They started this war. This is a residential area. And they targeted it.”