Military delegations from Ukraine, Russia and Turkey will meet U.N. officials in Istanbul on Wednesday to discuss a possible deal to resume safe exports of Ukraine grain from the major Black Sea port of Odessa as a global food crisis worsens, Reuters reported.

Turkish National Defense Minister Hulusi Akar announced the meeting on Tuesday. Turkey has been working with the United Nations to broker a deal after the war in Ukraine stoked global prices for grains, cooking oils, fuel, and fertilizer.

According to diplomats, elements of the plan being discussed include Ukrainian vessels guiding grain ships in and out through mined port waters; Russia agreeing to a truce while shipments move; and Turkey—supported by the United Nations—inspecting ships to allay Russian fears of weapons smuggling.

Ukraine and Russia are key global wheat suppliers, while Russia is also a large fertilizer exporter, and Ukraine—a significant producer of corn and sunflower oil.

Russia's sea blockade of Ukraine has stalled exports, leaving dozens of ships stranded and more than 20 million tons of grain stuck in silos at Odessa.

The coming harvest is also at risk as Ukraine is now short of storage space due to the halt in exports.

Even if a deal is struck to resume Ukrainian exports, diplomats say shipping and insurance companies will then require assurances to restart trade—given the risks in navigating mined waters. Ukraine fears that de-mining its ports would leave it far more vulnerable to Russian attack from the Black Sea.

The United Nations is also working to try and facilitate Russian grain and fertilizer exports, which Moscow says have been hindered by Western sanctions.

The United States says Russian grain and fertilizer are not sanctioned and has offered to give written assurances to shipping companies and importing countries.