The proposed roadmap begins with a full ceasefire of at least 30 days, to be followed by the return of all prisoners held by each side, and then a meeting between Ukrainian President Volodymyr Zelenskiy and Russian leader Vladimir Putin.

Under the blueprint, Moscow and Kyiv - with the participation of the United States and Europe - will work to hash out the terms on which they can agree to put a complete end to their three-year-old conflict, the biggest in Europe since World War Two.

Ukrainian officials said earlier this week that they had sent the blueprint to the Russian side in advance of the Istanbul talks. The framework Ukrainian terms for a peace deal as set out in the document seen by Reuters are largely the same as the terms previously put forward by Kyiv.