Ukrainian President Volodymyr Zelenskiy said the Russian forces fired more than 40 missiles targeting different cities and damaging infrastructure and commercial and residential buildings in different Ukrainian cities.
Kyiv city authorities said nine people were killed and at least 33 were wounded in the strike on the capital.
In Kryviy Rih, Zelenskiy's home city, 10 people were killed and 31 were injured, said Mayor Oleksandr Vilkul.
Another three people died in Pokrovsk in eastern Ukraine when missiles hit an industrial facility, the Donestk regional governor said.
"All services are involved to save as many people as possible," Zelenskiy said on the Telegram messaging app.
"And the whole world should use all its determination to finally put an end to the Russian strikes."
Russia has repeatedly denied targeting civilians.
Hungarian Prime Minister Viktor Orban made a surprise visit to Beijing where he met Xi Jinping. (AP PHOTO)
The major attack on Ukraine came as Hungarian Prime Minister Viktor Orban met Chinese President Xi Jinping to discuss a potential Ukraine peace deal, paying an unexpected visit to Beijing.
It is also the eve of a three-day NATO summit in Washington, which will look at how to reassure Ukraine of the alliance's unwavering support and offer Ukrainians hope that their country can come through Europe's biggest conflict since World War II.
Kyiv Mayor Vitali Klitschko said the attack on the capital was one of the heaviest since the start of Russia's invasion in February 2022.
He said the city's main children's hospital was damaged in the strike. Windows were smashed and panels ripped off.
Parents holding babies walked out into the street, dazed and sobbing.
"We heard an explosion, then we were showered with debris," Svitlaka Kravchenko, 33, told Reuters after she and her husband Viktor, went out from the shelter.
Their two-month old baby had been unharmed, but Svitlana had suffered cuts, and their car was buried under the rubble of the destroyed building across the courtyard from the main ward.
"It was scary. I couldn't breathe, I was trying to cover (my baby). I was trying to cover him with this cloth so that he could breathe," she said.
Local and regional authorities said industrial facilities, infrastructure and residential and commercial buildings were damaged in Kyi, Kryviy Rih, Dnipro, Pokrovsk, Kramatarosk and others.
With AP
