Ukraine and Russia will sign a breakthrough agreement on Friday, designed to help relieve a global food crisis caused by blocked Black Sea grain exports. This marks the first major deal between the warring sides since Russia"s February invasion of its neighbour, and comes as global food prices have soared, and people in some of the world"s poorest countries facing starvation. The deal has been brokered by Turkey and the United Nations, and President Recep Tayyip Erdoğan will be joined by UN Secretary-General Antonio Guterres for a signing ceremony at 13:30 (GMT) in Istanbul"s lavish Dolmabahçe Palace. The first direct talks between the warring sides" military delegations since March -- attended in Istanbul last week by Turkish and UN officials -- came up with an initial draft for resolving the impasse. The sides were meant to have met again this week for the possible signature of a formal agreement. But Russian President Vladimir Putin threatened to derail the talks by warning on Tuesday that he expected any agreement also to address his own country"s blocked grain exports. Foreign Minister Sergey Lavrov was also reserved about any potential deal being reached, claiming that the authorities in Kyiv are blocking the talks. The five-month war is being fought across one of Europe"s most fertile regions by two of the world"s biggest producers of grain. Almost all of the grain is usually shipped out of the region across the Black Sea. Turkish Foreign Minister Mevlüt Çavuşoğlu on Thursday acknowledged Putin"s concerns. "When we resolve this issue, not only will the export path for grain and sunflower oil from Ukraine be opened, but also for products from Russia," he said. When we resolve this issue, not only will the export path for grain and sunflower oil from Ukraine be opened, but also for products from Russia." "Even if these Russian products are not affected by sanctions, there are blockages concerning maritime transport, insurance and the banking system," Çavuşoğlu added. "The United States and the EU have given promises to lift these." NATO member Turkey has enjoyed good working relations with both Moscow and Kyiv throughout the conflict. A member of Kyiv"s delegation for the negotiations said the shipments could resume from three ports under full Ukrainian control. "Exports would take place through three ports: Odesa, Pivdennyi and Chornomorsk. But in the future we hope we could expand them," Ukrainian lawmaker Rustem Umerov told reporters. He added that the safety of the shipments would be overseen by a UN monitoring group based in Istanbul. Umerov also said that Russian ships should not be allowed into Ukrainian waters as part of the anticipated agreement. "We do not trust them, even if they sign an agreement with the UN. This is an aggressor country," he said. — Agencies