Russia’s defence ministry, in a posting on the Telegram messaging app, said 94 Russians in Ukrainian captivity had been released after negotiations and would be taken to a medical institution to be examined.

Andriy Yermak, the head of Ukraine’s presidential administration, said 95 Ukrainian service members had been returned, including some wounded. They included members of the national guard and border guards.

Yermak said those released had been in action near the city of Mariupol, under Russian siege for weeks last year, the Chernobyl nuclear power plant, briefly held last year by Russian forces, from Serpent Island in the Black Sea and from Bakhmut, still a focal point of fighting in the east.