Russia and Ukraine conducted their fourth prisoner swap in a week, the Russian defense ministry said Saturday, and Russia handed over the bodies of 1,200 dead Ukrainian soldiers to Kyiv.

"We continue to take our people out of Russian captivity. This is the fourth exchange in a week," Ukrainian President Volodymyr Zelenskyy wrote on social media.

"In accordance with the Russian-Ukrainian agreements... another group of Russian servicemen was returned from the territory controlled by the Kyiv regime," Russia's defense ministry said on Telegram.

Kyiv also said it had received another batch of 1,200 unidentified bodies from Russia, which it said Russia claimed "belong to Ukrainian citizens, including military personnel," as part of the Istanbul agreements as well.

Ukraine did not say whether it returned any bodies to Russia.