Russia's decision to suspend its participation in the U.N.-brokered grain deal, following a blast on the bridge to Crimea, has raised concerns about global food security.
Poorer nations fear that resulting price increases will make food inaccessible.
The Kremlin denies any connection between the attack and the grain deal suspension.
The United Nations Secretary-General warns that the withdrawal will have a detrimental impact on people in need worldwide.
Russia withdrew from the deal due to unmet demands for a parallel agreement on food and fertilizer exports.
The interruption of grain exports from Ukraine and Russia could drive up food prices globally, particularly in impoverished nations.
Ukraine plans to resume grain exports without Russia's participation and seeks support from Turkey.
The recent blast on the bridge highlights the vulnerability of Russia's Black Sea infrastructure.
The White House and the international community express concern, accusing Russia of using the agreement to weaken non-agricultural sanctions.
The EU pledges to secure food supplies for impoverished nations.