Negotiators for the warring sides in Istanbul appeared to make little progress on ceasefire terms or a possible summit between their presidents – with their meeting ending after less than an hour.

Russia and Ukraine discussed further prisoner swaps on Wednesday at a brief session of peace talks in Istanbul, but the sides remained far apart on ceasefire terms and a possible meeting of their leaders.

The warring sides remain far apart after the third round of U.S.-brokered peace negotiations on Wednesday. But there was progress on humanitarian issues.