Russia and Ukraine started a major prisoner exchange on Monday after days of wrangling cast doubt over the only concrete result of peace talks last week in Turkey.

Russian officials say that Moscow is still awaiting confirmation from Kyiv on a planned exchange of 6,000 bodies of soldiers killed in action and is accusing Ukraine of delaying the process

A large-scale prisoner exchange between Russia and Ukraine -- the only concrete outcome of peace talks -- was thrown into doubt Saturday after Moscow and Kyiv accused each other of delaying and thwarting the swap.