KYIV, Ukraine (AP) — Russia and Ukraine swapped hundreds more prisoners on Sunday, the third and last part of a major exchange that reflected a rare moment of cooperation in otherwise failed efforts to reach a ceasefire in the more than three years of war.

Hours earlier, the Ukrainian capital, Kyiv, and other regions came under a massive Russian drone-and-missile attack that killed at least 12 people and injured dozens. Ukrainian officials described it as the largest aerial assault since Russia’s full-scale invasion of Ukraine in February 2022.

Russia’s Defense Ministry said each side exchanged 303 soldiers, following the release of 307 combatants and civilians each on Saturday, and 390 on Friday — the biggest total swap of the war.

Ukraine’s President Volodymyr Zelenskyy confirmed Sunday’s exchange, saying on X that “303 Ukrainian defenders are home.” He noted that the troops returning to Ukraine were members of the “Armed Forces, the National Guard, the State Border Guard Service, and the State Special Transport Service.”

Nataliya Borovyk, the sister of released Ukrainian soldier Ihor Ulesov, was overwhelmed when she learned of her brother’s return.

“My uncle had to calm me down and put me in a taxi so I could get here,” she told The Associated Press. “A moment like that stays with you forever.”

Borovyk said the family had been waiting anxiously for news, and that she had hoped her brother might be released in the first part of the exchange on Friday.

“We were worried about all the guys. He wasn’t there on Friday, but I was here — I at least greeted them, I stood there until the very end and waited, (hoping) maybe he would appear after all.”

In talks held in Istanbul earlier this month — the first time the two sides met face to face for peace talks — Kyiv and Moscow agreed to swap 1,000 prisoners of war and civilian detainees each. The exchange has been the only tangible outcome from the talks.

The scale of the onslaught was stunning — Russia hit Ukraine with 367 drones and missiles, the largest single aerial attack of the war, according to Yuriy Ihnat, a spokesperson for Ukraine’s Air Force.

In all, Russia used 69 missiles of various types and 298 drones, including Iranian-designed Shahed drones, he told The Associated Press.

There was no immediate comment from Moscow on the strikes.

For Kyiv, the day was particularly somber as the city observed Kyiv Day, a national holiday that falls on the last Sunday in May, commemorating its founding in the 5th century,

Zelenskyy said Russian missiles and drones hit more than 30 cities and villages, and urged Western partners to ramp up sanctions on Russia — a longstanding demand of the Ukrainian leader but one that despite warnings to Moscow by the United States and Europe has not materialized in ways to deter Russia.

“These were deliberate strikes on ordinary cities,” Zelenskyy wrote on X, adding that Sunday’s targets included Kyiv, Zhytomyr, Khmelnytskyi, Ternopil, Chernihiv, Sumy, Odesa, Poltava, Dnipro, Mykolaiv, Kharkiv and Cherkasy regions.

“America’s silence, the silence of others in the world, only encourages” Russian President Vladimir Putin, he said. “Without truly strong pressure on the Russian leadership, this brutality cannot be stopped. Sanctions will certainly help.”

Russia’s Defense Ministry, meanwhile, said its air defenses shot down 110 Ukrainian drones overnight.

Sounds of explosions boomed throughout the night in Kyiv and the surrounding area as Ukrainian air defense persisted for hours in efforts to shoot down Russian drones and missiles. At least four people were killed and 16 were injured in the capital itself, according to the security service.

“A difficult Sunday morning in Ukraine after a sleepless night,” Ukrainian Foreign Minister Andrii Sybiha said on X, adding that the assault “lasted all night.”

Fires broke out in homes and businesses, set off by falling drone debris.

In Zhytomyr region, west of Kyiv, the emergency service said three children were killed, aged 8, 12 and 17. Twelve people were injured in the attacks, it said. At least four people were killed in the Khmelnytskyi region, in western Ukraine. One man was killed in Mykolaiv region, in southern Ukraine.

Kyiv Mayor Vitali Klitschko said a student dormitory in Holosiivskyi district was hit by a drone and one of the building’s walls was on fire. In Dniprovskyi district, a private house was destroyed and in Shevchenkivskyi district, windows in a residential building were smashed.

The scale of Russia’s use of aerial weapons aside, the attacks over the past 48 hours have been among the most intense strikes on Ukraine since the February 2022 invasion.

In Markhalivka, just outside Kyiv where several village homes were burned down, the Fedorenkos watched their ruined home in tears.

“The street looks like Bakhmut, like Mariupol, it’s just terrible,” said 76-year-old Liubov Fedorenko, comparing their village to some of Ukraine’s most devastated cities. She told the AP she was grateful her daughter and grandchildren hadn’t joined them for the weekend.

“I was trying to persuade my daughter to come to us,” Fedorenko said, adding that she told her daughter, “After all, you live on the eighth floor in Kyiv, and here it’s the ground floor.’”

“She said, ‘No, mum, I’m not coming.’ And thank God she didn’t come, because the rocket hit (the house) on the side where the children’s rooms were,” Fedorenko said.

Ivan Fedorenko, 80, said he regrets letting their two dogs into the house when the air raid siren went off. “They burned to death,” he said. “I want to bury them, but I’m not allowed yet.”

The POW exchange was the latest of scores of swaps since the war began but also the biggest involving Ukrainian civilians.

Still, it has not halted the fighting. Battles have 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.

Russia’s Defense Ministry quoted Yaroslav Yakimkin of the “North” group of Russian forces as saying Sunday that Ukrainian troops have been pushed back from the border in the Kursk region, which Putin visited days ago.

“The troops continue to advance forward every day,” Yakimkin said, adding that Russian forces have taken Marine and Loknya in Ukraine’s northeastern Sumy region, which borders Kursk, over the past week, and were advancing in the Kharkiv region around the largely destroyed town of Vovchansk.

Speaking on Russian state TV on Sunday, a Russian serviceman said that Putin was reportedly flying over the Kursk region in a helicopter when the area came under intense Ukrainian drone attack during his visit.

Putin’s helicopter was “virtually at the epicenter of repelling a large-scale attack by the enemy’s drones,” said Yuri Dashkin, described as commander of a Russian air defense division. He added that Russian air defense units shot down 46 drones during the incident.

Yeroshenko reported from Markhalivka, Ukraine. Associated Press writers Elise Morton in London and Volodymyr Yurchuk in Kyiv, Ukraine, contributed to this report.

Follow AP’s coverage of the war in Ukraine at https://apnews.com/hub/russia-ukraine