This handout photograph taken and released by Ukrainian State Emergency Service Press Service on May 25, 2025 shows firefighters operating on burning houses following Russian strike in Kyiv region, amid Russian invasion in Ukraine. Photo: AFP
Russian strikes killed at least 12 people in Ukraine overnight into Sunday, officials said, as Kyiv and Moscow traded fire amid an ongoing major prisoner swap.

Ukraine's emergency services described a night of "terror" as Russia launched a second straight night of massive air strikes on Ukraine, including on the capital Kyiv.

The attacks came as the two sides pursued their biggest prisoner swap since Moscow launched its full-scale invasion in February 2022, and as the United States tries to broker a ceasefire to halt the three-year-old war.

The death toll from the latest Russian strikes included two children, aged eight and 12, and a 17-year-old, killed in the northwestern region of Zhytomyr, officials said.

"Without truly strong pressure on the Russian leadership, this brutality cannot be stopped," Ukrainian President Volodymyr Zelensky said on social media.

"Sanctions will certainly help," he said, calling on the United States, European countries and "all those around the world who seek peace" to show their "determination" to make Moscow halt the war.

Ukraine's military said early Sunday it had shot down 45 Russian missiles and 266 attack drones overnight.

Russian meanwhile said it had brought down 110 Ukrainian drones overnight.

Four people were reported dead in Ukraine's western Khmelnytskyi region, four in the Kyiv region and one in Mykolaiv in the south.

Emergency services said 16 people were also injured in the Kyiv region, including three children, in the "massive night attack".

"We saw the whole street was on fire," a 65-year-old retired woman, Tetiana Iankovska, told AFP in Makhalivka village just southwest of Kyiv.

Another retiree who survived the strikes, Oleskandr, 64, said he had no faith in talks around a ceasefire.

"We don't need talks, but weapons, a lot of weapons to stop them (the Russians). Because Russia understands only force, nothing else," he said.

- Major prisoner exchange -

The renewed attacks came after Russia launched 14 ballistic missiles and 250 drones overnight Friday to Saturday, which wounded 15, according to Ukrainian officials.

Zelensky said that, even with the ramped-up hostilities, he expected the prisoner swap agreed during talks in Istanbul on May 16 to continue.

On Saturday, 307 Russian prisoners of war were exchanged for the same number of Ukrainian soldiers, according to announcements in Kyiv and Moscow.

Both sides received 390 people in the first stage on Friday.

They are expected to exchange 1,000 each in total.

Russia has signalled it will send Ukraine its terms for a peace settlement after the exchange, without saying what those terms would be.

The two enemies have held regular prisoner swaps, but this would be the largest so far, if completed.

An AFP reporter saw some of the formerly captive Ukrainian soldiers arrive at a hospital in the northern Chernigiv region, emaciated but smiling and waving to crowds waiting outside.

"It's simply crazy. Crazy feelings," 31-year-old Konstantin Steblev, a soldier, told AFP Friday as he stepped back onto Ukrainian soil after three years in captivity.

- Diplomatic push -

US President Donald Trump on Friday congratulated the two countries for the swap.

"This could lead to something big?" he wrote on his Truth Social platform.

Trump's efforts to broker a ceasefire in Europe's biggest conflict since World War II have so far been unsuccessful, despite his pledge to rapidly end the fighting.

One of the soldiers formerly held captive, 58-year-old Viktor Syvak, told AFP it was hard to express his emotional homecoming.

Captured in the Ukrainian port city of Mariupol, he had been held for 37 months and 12 days.

"It's impossible to describe. I can't put it into words. It's very joyful," he said.

After more than three years of fighting, both countries are holding thousands of POWs.

Russia is believed to have the larger share, with the number of Ukrainian captives estimated to be between 8,000 and 10,000.