Five people were killed and 25 injured in a Russian attack on Dnipro, in Ukraine's east, regional governor Oleksandr Hanzha said on Telegram.
All those injured were hospitalised and were reported to be in moderate condition, he said, posting pictures of heavily damaged residential buildings, burnt-out vehicles and a destroyed children's playground.
In Kyiv, at least four were killed and 51 others were injured across the capital, according to Tymur Tkachenko, the head of the capital's military administration.
Kyiv Mayor Vitali Klitschko said a suspected missile strike on a 24-storey apartment building triggered a collapse, with people likely trapped under the rubble.
Other buildings, including a nine-storey apartment block, caught fire from suspected missile debris, he said.
"In the Obolon district, cars are burning after being struck by falling missile debris. There are also fires at two locations in open areas, including one near a kindergarten," Klitschko said.
Thousands of residents of Kyiv were taking refuge inside metro stations and other shelters, witnesses said, after air raid warnings that covered much of the country early on Tuesday.
Ukrainian President Volodymyr Zelenskiy reiterated warnings of a possible massive Russian strike and urged residents to pay special attention to air raid alerts.
"Intelligence warnings regarding Russian strikes remain in effect. A massive strike is possible, they have prepared one," Zelenskiy said in his nightly video address.
"Our defenders are ready 24/7 to the fullest extent possible with the supplies currently available."
Russia last week warned it intended to launch "systematic strikes" on targets in Kyiv linked to the Ukrainian military as well as decision-making centres, and urged foreigners to leave.
It said the action was in response to a drone strike last month on a dormitory in Ukraine's Russian-held Luhansk region, which killed 21 people. Ukraine denied carrying out the attack.
In Ukraine's northeastern Kharkiv region, Governor Oleh Syniehubov said on Telegram at least 10 people were wounded, including an 11-year-old girl, in Russian shelling overnight.
Air defence systems were also repelling drone attacks over Sevastopol, a Russian naval fleet base, in Russia-occupied Crimea, authorities said.
Reuters could not independently verify the reports.
Russia has targeted Ukraine's power supplies and infrastructure while Ukraine has stepped up attacks on oil facilities inside Russia this year, sometimes resulting in casualties. Both sides deny targeting civilians.
The war in Ukraine has ground on for more than four years since Russia launched its full-scale invasion in February 2022. Efforts to end the conflict have made little progress with the US administration of Donald Trump focused on conflicts in the Middle East.
with DPA