It was the first major bombardment since an air attack on Kyiv killed at least 21 people last month.
Tymur Tkachenko, head of the Kyiv City Administration, confirmed Sunday's casualties on Telegram, and said 10 others were injured in the attack that targeted civilian areas across the city.
A 12-year-old girl was among the dead.
"The Russians have restarted the child death counter," he wrote.
Thick black smoke could be seen rising from a blast near the city centre.
The strikes that began overnight and continued after dawn targeted residential buildings, civilian infrastructure, a medical facility and a children's nursery, according to Kyiv mayor Vitali Klitschko, who said damage was reported at more than 20 locations.
At Kyiv's central train station, passengers arrived to the crackle of anti-aircraft gunfire and the low buzz of attack drones. Mostly women, they waited quietly in a platform underpass until the air raid alert ended.
"The sky has turned black again," said one woman, who gave only her first name, Erika. "It's happening a lot."
At a multi-storey residential building heavily damaged by a drone attack, a large section of the upper floors was gutted and windows blown out.
Emergency services personnel, including firefighters with an extended ladder, used power saws to clear the debris. Piles of glass littered nearby pavements as building residents, some looking shaken, sat on benches.
Ukraine's foreign minister Andrii Sybiha said the assault had involved "hundreds of drones and missiles".
Writing on X, Sybiha added: "We must maximise the cost of further escalation for Russia."
Russian officials did not immediately comment on the attacks.
Meanwhile, Poland has closed its airspace near its southeastern cities of Lublin and Rzeszow due to "unplanned military activity related to ensuring state security", flight tracking service Flightradar24 says.
The Polish armed forces said it scrambled aircraft to ensure the security of its airspace after Russia launched strikes on Ukraine.
"In connection with the activity of the Russian Federation's long-range aviation carrying out strikes on the territory of Ukraine, Polish and allied aircraft have begun operating in our airspace," the military said in a post on X.Â
It described the actions as preventive and aimed at securing airspace and protecting citizens.
US President Donald Trump said this week that he endorsed the idea of shooting down Russian jets that violate NATO airspace, part of a rhetorical shift in which he appeared to mock Russia's military performance in Ukraine and call it a paper tiger.
As Russia's war rages in Ukraine, tensions have mounted along NATO's eastern flank in recent weeks as Estonia has accused the Kremlin of sending three fighter jets into its airspace and NATO jets shot down Russian drones in Polish airspace.
Ukrainian President Volodymyr Zelenskiy commented on Russia's attacks against European countries.
"Russia is testing their ability to defend themselves and trying to influence societies so people begin to ask: "If we can't protect ourselves, why should we keep supporting Ukraine?" This is intended to reduce assistance to Ukraine, especially ahead of winter," he said on X.
Ukraine relies heavily on foreign air defence systems to protect its cities from Russian attacks.
with DPA and PA
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