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.

Deaths have been reported on either side of the border, just hours after a third round of ceasefire talks took place in Turkey.

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.