Russia carried out a deadly large-scale wave of strikes against Ukraine, firing hundreds of drones and dozens of missiles overnight.
Ukrainian President Volodymyr Zelensky said Kyiv was the main target, but other areas were also hit, with about 100 people injured.
Four people were killed in the capital and wider region, with loud explosions heard across the area throughout the night. Dozens of residential buildings, a school, an opera house and a museum were damaged.
Russia's defence ministry said the Oreshnik hypersonic missile was used in the strikes, which it described as coming in response to Ukraine's "attacks on civilian infrastructure". Ukraine's military denies targeting civilians.
Russian President Vladimir Putin launched a full-scale invasion of Ukraine in February 2022.
Earlier this week, he accused Kyiv of hitting a student dormitory in the town of Starobilsk on Friday, in which Russian officials said 21 people were killed.
Ukraine's military said its forces did carry out an attack in Starobilsk in Russian-occupied eastern Ukraine overnight on Friday, but maintained that it struck an elite Russian drone military unit.
European leaders have condemned the overnight Russian strikes on Sunday, which came after warnings from Zelensky that Russia was planning an attack, and that it may have been preparing to use the Oreshnik missile.
It reportedly travels at more than 10 times the speed of sound, is hard to intercept, and is known to be capable of carrying both conventional and nuclear warheads.
Zelensky - who on Sunday visited a number of damaged buildings in Kyiv - said that Russia had launched the Oreshnik missile against the city of Bila Tserkva in the Kyiv region.
Ukraine's presidential office later said it was not confirming that, saying work was ongoing to determine exactly what had been used.
It would be the third time Russia has used the Oreshnik missile in the conflict.
Both French President Emmanuel Macron and German Chancellor Friedrich Merz condemned the reported use of the weapon, while EU foreign policy chief Kaja Kallas described it as a "political scare-tactic and reckless nuclear-brinkmanship"
UK Foreign Secretary Yvette Cooper lamented the "awful scenes" in Kyiv and vowed to "keep up pressure on Russia".
At the French Open tennis tournament in Paris, tearful Ukrainian player Marta Kostyuk said "all my heart and all my thoughts go to the people of Ukraine" after winning in the first round.
And Ukrainian boxer Oleksandr Usyk, who last night defended his heavyweight world titles in a fight against Dutchman Rico Verhoeven in Egypt, said: "I know right now, Ukrainian people are sitting in the bomb shelter, my daughter too, in a bomb shelter, sent me a message saying: 'Papa, I love you, you will win."
Ukraine's air force said that from 18:00 local time (15:00 GMT) on Saturday, it detected 90 missiles and 600 drones.
It said that early data showed 55 ballistic and cruise missiles and 549 drones were shot down or intercepted, while 19 missiles may not have reached their targets.
It also acknowledged that there were 16 direct missile and 51 drone hits in 54 locations.
Residential buildings, shopping centres and emergency services buildings were reportedly struck.
Zelensky said 69 people had been injured in the capital alone, while a water-supply facility was also attacked and the Chornobyl Museum in Kyiv had been "effectively destroyed".
Ukraine's Interior Minister Ihor Klymenko said the attack on the museum was "a deliberate attack on history, memory, and truth". Footage and pictures shared by the ministry showed broken glass windows and rubble scattered everywhere.
Russia's defence ministry said it did not carry out strikes against Ukraine's civilian infrastructure, but that command posts of Ukraine's ground forces and the defence ministry's main intelligence directorate were hit.
Ukraine has not confirmed this.
Kyiv's Mayor Vitali Klitschko earlier said two people had been killed in the city itself, with 36 others, including two children, in hospital.
A person was killed after a nine-storey residential building in the central Shevchenko district was hit and a fire broke out on the top floors.
In the same district, a strike near an air raid shelter at a school blocked its entrance with debris, trapping several people inside.
Emergency services rushed to multiple scenes of damage across the city, putting out blazes, clearing debris and treating the injured.
In the wider Kyiv region, a further two people were also killed, according to regional head Mykola Kalashnyk.
He described the attack as "deliberate terror against peaceful people", adding that "emergency services are working in all places".
Outside Kyiv, the regions of Cherkasy, Kharkiv, Odesa, Poltava, Sumy, and Zhytomyr have also come under attack, according to Ukrainian Foreign Minister Andrii Sybiha.
