Russia and Turkey made little headway on Wednesday in talks aimed at securing safe passage for Ukrainian grain exports, as a Russian sea blockade triggered new warnings of deadly famine.
Prior to the war, Ukraine was a major exporter of wheat, corn and sunflower oil, but shipments have been blocked since Russia invaded its neighbour in late February, causing food prices to soar worldwide.
Countries in the Middle East and Africa depend on Ukraine's exports, raising fears of hunger in those countries.
At the request of the United Nations, Turkey has offered its services to escort maritime convoys from Ukrainian ports, despite the presence of mines -- some of which have been detected near the Turkish coast.