Ukraine and Russia agreed to swap 1,000 prisoners of war each during face-to-face talks in Istanbul on 16 May. View on euronews

A major prisoner exchange between Russia and Ukraine began Friday, the countries said, in one of the few signs of progress from their direct talks last week in Istanbul — part of a U.S.-led effort that so far has failed to produce a ceasefire in the 3-year-old war.

This could lead to something big???” US President Donald Trump said on social media, apparently referring to international diplomatic efforts to stop the fighting.