Russia had launched 1567 drones since the start of Wednesday, Ukrainian President Volodymyr Zelenskiy said. At least 27 civilians have been killed over the two days, officials said on Thursday.
Russian President Vladimir Putin on Saturday said the war, which has killed hundreds of thousands of people and ravaged swathes of Ukraine over more than four years, was "coming to an end".
But, as Moscow launched what Ukraine said were more than 670 attack drones and 56 missiles overnight, Zelenskiy did not sound positive.
"These are definitely not the actions of those who believe the war is coming to an end," he said.
"It's important that partners do not remain silent about this strike. And it is equally important to continue supporting the protection of our skies."
Kyiv was the main target of the overnight strikes, Zelenskiy said. Ukraine's State Emergency Services said at least 21 people, including three children, were killed in the capital and Mayor Vitali Klitschko announced a day of mourning for Friday.
In a statement issued after midnight, the Emergency Services said rescue operations were continuing round the clock.
There was no immediate comment from Moscow on Thursday's attacks.
Reuters TV footage from Kyiv showed emergency workers moving carefully across piles of rubble and cutting through concrete at the site of a strike on a nine-storey residential building where an entire section had been destroyed.
Speaking in his nightly video address, Zelenskiy said that, according to initial analysis, a recently manufactured Russian Kh-101 missile had struck the building. He called for renewed diplomatic efforts to keep such technology out of Russian hands.
More than 1500 rescue workers have been deployed across Ukraine to deal with the aftermath of the strikes, including nearly 600 in Kyiv.
Zelenskiy said overall 180 facilities had been damaged in Ukraine, including more than 50 residential buildings.
He said a UN Office for the Coordination of Humanitarian Affairs vehicle had come under fire from drones during a humanitarian mission in the southern city of Kherson.
In Ukraine's second-largest city, Kharkiv, 28 people including three children were wounded and civilian infrastructure was targeted, regional governor Oleh Syniehubov said.
Ukraine's energy ministry said electricity supplies in 11 regions had been disrupted. The strikes also targeted port infrastructure in the southern Odesa region and railways, officials said.
Foreign Minister Andrii Sybiha said the attack - while US President Donald Trump is visiting China - showed Russia wanted to continue fighting despite Washington's peace push, and that pressure was needed on Moscow to end the war.
"I am certain that the leaders of the United States and China have enough leverage over Moscow to tell Putin to finally end the war," he wrote on X.