Russia and Ukraine exchanged hundreds more prisoners Saturday as part of a major swap that amounted to a rare moment of cooperation in otherwise failed efforts to reach a ceasefire. The exchange came hours after Kyiv came under a large-scale Russian drone and missile attack that left at least 15 people injured.

Ukraine's President Volodymyr Zelenskyy and Russia’s defense ministry said each side brought home 307 more soldiers on Saturday, a day after each released a total of 390 combatants and civilians. Further releases expected over the weekend are set to make the swap the largest in more than three years of war.

“We expect more to come tomorrow,” Zelenskyy said on his official Telegram channel. Russia's defense ministry also said it expected the exchange to be continued, though it did not give details.

Hours earlier, explosions and anti-aircraft fire were heard throughout Kyiv as many sought shelter in subway stations as Russian drones and missiles targeted the Ukrainian capital overnight.

In talks held in Istanbul earlier this month — the first time the two sides met face to face for peace talks since Russia's 2022 full-scale invasion — Kyiv and Moscow agreed to swap 1,000 prisoners of war and civilian detainees each.

‘A difficult night’

Officials said Russia attacked Ukraine with 14 ballistic missiles and 250 Shahed drones overnight while Ukrainian forces shot down six missiles and neutralized 245 drones — 128 drones were shot down and 117 were thwarted using electronic warfare.

The Kyiv City Military Administration said it was one of the biggest combined missile and drone attacks on the capital.

“A difficult night for all of us,” the administration said in a statement.

Posting on X, Ukraine's Foreign Minister Andrii Sybiha called it “clear evidence that increased sanctions pressure on Moscow is necessary to accelerate the peace process."

Posting on X, U.K. Foreign Secretary David Lammy spoke of “another night of terror for Ukrainian civilians.”

“These are not the actions of a country seeking peace,” Lammy said of the Russian strike.

Katarina Mathernová, the European Union's ambassador to Kyiv, described the attack as “horrific."

“If anyone still doubts Russia wants war to continue — read the news,” Katarina Mathernová wrote on the social network.

Air raid alert in Kyiv

The debris of intercepted missiles and drones fell in at least six Kyiv city districts. According to the acting head of the city's military administration, Tymur Tkachenko, six people required medical care after the attack and two fires were sparked in Kyiv's Solomianskyi district.

The Obolon district, where a residential building was heavily damaged in the attack, was the hardest hit with at least five wounded in the area, the administration said.

Kyiv hit by massive Russian missile and drone attack

Yurii Bondarchuk, a local resident, said the air raid siren “started as usual, then the drones started to fly around as they constantly do.” Moments later, he heard a boom and saw shattered glass fly through the air.

“The balcony is totally wiped out, as well as the windows and the doors,” he said as he stood in the dark, smoking a cigarette to calm his nerves while firefighters worked to extinguish the flames.

The air raid alert in Kyiv lasted more than seven hours, warning of incoming missiles and drones.

Kyiv's mayor, Vitalii Klitschko, warned residents ahead of the attack that more than 20 Russian strike drones were heading toward the city. As the attack continued, he said drone debris fell on a shopping mall and a residential building in Obolon. Emergency services were headed to the site, Klitschko said.

Separately, 13 civilians were killed on Friday and overnight into Saturday in Russian attacks in Ukraine's south, east and north, regional authorities said.

Three people died after a Russian ballistic missile targeted port infrastructure in Odesa on the Black Sea, local Gov. Oleh Kiper reported. Russia later said the strike Friday targeted a cargo ship carrying military equipment.

Russia’s defense ministry on Saturday claimed its forces overnight struck various military targets across Ukraine, including missile and drone-producing plants, a reconnaissance center and a launching site for anti-aircraft missiles.

A complex deal

The prisoner swap on Friday was the first phase of a complicated deal involving the exchange of 1,000 prisoners from each side.

It took place at the border with Belarus, in northern Ukraine, according to a Ukrainian official who spoke on condition of anonymity because he was not authorized to speak publicly.

The released Russians were taken to Belarus for medical treatment, the Russian Defense Ministry said.

POWs arrived at the medical facility in the Chernihiv region for a second day on Saturday. But for many their arrival was bittersweet.

Those who were not reunited with their loved ones took solace in the released POWs providing some information about when their relatives were last seen.

Anna Marchenko, the daughter of a missing Ukrainian serviceman, was elated when a released POW said they had seen her father.

“This is such a big news. It’s like a fresh breath of air,” she said. “I didn’t see him, but at least it’s some news. At least it’s news that gives us the opportunity to continue to breathe and live in peace."

However, the exchange — the latest of dozens of swaps since the war began and the biggest involving Ukrainian civilians so far — did not herald a halt in the fighting.

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Battles continued along the roughly 1,000-kilometer (620-mile) front line, where tens of thousands of soldiers have been killed, and neither country has relented in its deep strikes.

After the May 16 Istanbul meeting, Turkish Foreign Minister Hakan Fidan called the prisoner swap a “confidence-building measure” and said the parties had agreed in principle to meet again.

But Kremlin spokesman Dmitry Peskov said on Friday that there has been no agreement yet on the venue for the next round of talks as diplomatic maneuvering continued.

Russian Foreign Minister Sergey Lavrov said Moscow would give Ukraine a draft document outlining its conditions for a “sustainable, long-term, comprehensive” peace agreement, once the ongoing prisoner exchange had finished.

Far apart on key conditions

European leaders have accused Russian President Vladimir Putin of dragging his feet in peace efforts while he tries to press his larger army’s battlefield initiative and capture more Ukrainian land.

The Istanbul meeting revealed that both sides remained far apart on key conditions for ending the fighting. One such condition for Ukraine, backed by its Western allies, is a temporary ceasefire as a first step toward a peaceful settlement.

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Russia’s Defense Ministry said that overnight and early on Saturday its forces shot down over 100 Ukrainian drones over six provinces in western and southern Russia.

The drone strikes injured three people in the Tula region south of Moscow, local Gov. Dmitriy Milyaev said, and sparked a fire at an industrial site there.

Andriy Kovalenko, of Ukraine’s National Security and Defense Council, said Saturday the drones hit a plant in Tula that makes chemicals used in explosives and rocket fuel.