Russia and Ukraine have agreed on an exchange of 40 prisoners of war, Russian Human Rights Commissioner Tatyana Moskalkova said on Wednesday after meeting her Ukrainian counterpart Dmytro Lubinets in Turkey.

Moskalkova and Lubinets met on the sidelines of an international ombudsman conference in Ankara. Photos showed them sitting on opposite sides of a table.

The initial talks lasted for some 40 minutes. A second round began at 0920 GMT.

As they met, a battle was raging for the small town of Soledar in eastern Ukraine.

Earlier, Moskalkova had said on the Telegram messaging app that she and Lubinets had discussed humanitarian assistance for citizens of both Russia and Ukraine.

They were later expected to visit the Turkish presidential palace, where President Tayyip Erdogan was scheduled to make a speech for the conference at 1130 GMT.

A Turkish source said Moskalkova and Lubinets might discuss a humanitarian corridor and the situation of children who had fled the war.

Russia and Ukraine have conducted numerous prisoner swaps - most recently on Sunday - in the course of the war, which is now in its 11th month.