Ukraine and Russia have completed their three-day exchange of prisoners. They each swapped 1,000 people in the largest such move yet between the two sides since Russia began to invade Ukraine in 2022.

Ukraine and Russia announced on Sunday, the last day of the exchange, that they each released 303 service members earlier in the day.

The two countries agreed to the swap during their direct talks in the Turkish city of Istanbul on May 16. That was the first face-to-face meeting between Ukraine and Russia in about three years.

Ukrainian President Volodymyr Zelenskyy took to social media, pledging to bring back "every single one" of his compatriots who remain in Russian captivity.

Meanwhile, Russia unleashed a barrage of drone and missile attacks on Ukraine from Saturday night into Sunday.

The stricken areas included the capital Kyiv and the northwestern region of Zhytomyr. At least 12 people were killed, including three children.

The attacks involved nearly 300 drones and almost 70 missiles, including ballistic ones.

Reuters news agency describes them as "the largest aerial attack" since Russia started the invasion.

Russian Foreign Minister Sergey Lavrov said on Friday that Moscow was "working hard" to prepare "a draft document outlining the terms for achieving a durable, lasting, and comprehensive resolution."

He added that once the prisoner exchange was completed, Russia would "be ready to present" the draft to Ukraine.

It remains unclear whether progress can be made toward realizing a ceasefire under terms sought by Ukraine.