Ankara's military delegation will travel to Russia this week to discuss details of a possible safe sea corridor in the Black Sea to export Ukrainian grain, Turkish presidency sources said on Tuesday.
Russia's TASS agency confirmed plans for the talks citing Kremlin spokesman Dmitry Peskov.
Russia's Feb. 24 invasion of Ukraine halted Kyiv's Black Sea grain exports, causing global food shortages, though Moscow blames Western sanctions for the crisis. The United Nations has appealed to both sides, as well as their maritime neighbor and NATO member Turkey, to agree a corridor.
Ankara has so far held talks with Moscow and the UN on the planned corridor, but has said any final agreement would require all parties to meet in Istanbul, where Turkey says the plan's implementation would be monitored.
The sources said a four-way meeting between Turkey, Ukraine, Russia and the United Nations would be held in Istanbul in the coming weeks, possibly with the participation of President Tayyip Erdogan and UN Secretary General Antonio Guterres.
Turkish broadcaster Haberturk also earlier reported about the planned meeting.
The sources said the plan envisaged creating three corridors from Ukraine's Black Sea port city of Odesa under Kyiv's supervision, and that both Ukrainian and Russian food products would be shipped from there.
They said 30-35 million tons of grain could be shipped from there in the next six to eight months.
Asked about plan's outline presented by the sources, UN spokesman Stéphane Dujarric said "the discussions on these issues are continuing," without further elaborating.
The news of planned upcoming talks come a day after Erdogan and Guterres discussed plans for the corridor in a phone call. Erdogan's office said he told the UN chief that Turkey was "continuing mutual efforts" to establish the corridor.
Both Ukraine and Russia have set out a series of conditions to agree the plan. Moscow wants some western sanctions lifted to help facilitate its grain and fertilizer exports, while Kyiv seeks security guarantees for its ports.