Russia launched a major attack on the Ukrainian capital Kyiv and killed at least 13 people in strikes across the country, just hours after the two sides began a major prisoner exchange.

At least four people have been killed in the eastern Donetsk region, five in the southern Kherson and Odesa regions, and four in the northern Kharkiv region in the past 24 hours, according to regional officials.

Ukraine?s Air Force said Russia launched 14 ballistic missiles and 250 attack drones on the country, with the ?main focus? being the capital Kyiv. It said air defenses shot down six of those missiles and 245 of the drones, with projectiles also hitting the Dnipro, Odesa, Kharkiv, Donetsk and Zaporizhzhia regions.

?It was a difficult night for all of Ukraine,? President Volodymyr Zelensky said on Telegram, expressing his condolences to families and loved ones of the injured.

At least 18 people were injured in Kyiv which came under a large-scale Russian drone and missile attack overnight into Saturday, according to police.

The city?s mayor Vitali Klitschko said the attack triggered fires and left debris strewn throughout the city. Multiple residential buildings were damaged, officials said.

Explosions and loud sirens could be heard blaring across the capital. Several fires could be seen against the nighttime skyline.

Ukrainian parliament member Kira Rudik told CNN she spent the night hiding ?under the stairs? in Kyiv during the overnight bombardment. ?It was terrifying, it felt honestly like armageddon, the explosions were everywhere,? she said.

The nighttime attack came after Russia and Ukraine completed the first phase of what is expected to be the biggest prisoner exchange since the start of the war.

The swap started on Friday and will continue on Saturday and Sunday, with Kyiv and Moscow expected to swap 2,000 people ? 1,000 from each side.

The agreement to release 1,000 prisoners on each side was the only significant outcome of the meeting between Kyiv and Moscow in Istanbul last week, which marked the first time the two sides have met directly since soon after Russia?s full-scale unprovoked invasion of Ukraine in February 2022.

Ukrainian Foreign Minister Andrii Sybiha said that the country?s air defense worked ?non-stop? to repel Russian air attacks overnight.

?One week has passed since the Istanbul meeting, and Russia has yet to send its ?peace memorandum.? Instead, Russia sends deadly drones and missiles at civilians,? he said.

Meanwhile, Russia?s defense ministry claimed it destroyed 94 Ukrainian UAVs over Russian territory, mostly over the Belgorod and Bryansk regions. Some UAVs were also shot down over the Kursk, Lipetsk, Voronezh and Tula regions too, it added.

The governor of the Tula region, Dmitry Miliaev, said three people were injured, including two who were hospitalized.

The Istanbul meeting was initially proposed by Russian President Vladimir Putin in response to a ceasefire-or-sanctions ultimatum given to Moscow by Kyiv?s European allies ? which many saw as a clear attempt by the Kremlin leader to distract and delay.

Ukraine and its allies demanded that Russia agree to an immediate and unconditional ceasefire in Istanbul, but there was no major breakthrough. (CNN)

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