Russia and Ukraine exchanged hundreds of prisoners on Saturday, part of a major agreement despite ceasefire negotiations remaining stalled.

The exchange came just hours after Ukraine was hit by a large-scale drone and missile attack from Russia that left at least 15 people injured. Despite the ongoing violence, both countries confirmed the return of 307 soldiers on Saturday, one day after an earlier release of 390 combatants and civilians on both sides, according to the Associated Press.

With more releases expected over the weekend, the round of exchanges could become the largest prisoner swap of the war to date.

“We expect the process to continue tomorrow,” Ukrainian President Volodymyr Zelensky confirmed on social media. " Our goal is to bring every single person back from Russian captivity. We continue cooperating with our partners to make this possible.”

he agreement follows attempted peace talks earlier this month in Istanbul, where both sides met face-to-face for the first time since the war began. There, Ukraine and Russia committed to releasing 1,000 prisoners each, including prisoners of war and civilian detainees. Zelensky’s office estimated that more than 8,000 Ukrainian soldiers have been captured since Russia’s full-scale invasion began in February 2022.

Saturday’s exchange occurred against the backdrop of another major Russian assault on Ukraine, involving 14 ballistic missiles and 250 drones overnight. Ukrainian forces reported intercepting six missiles and neutralizing 245 drones. Of those, 128 drones were shot down, while 117 were disabled using electronic warfare, according to officials.

Kyiv’s City Military Administration described the attack as one of the largest of the war, calling it a “difficult night for all of us” in a statement.