Russia says it has indefinitely suspended its participation in a deal that facilitated agricultural exports from Ukraine.

The Russian foreign ministry made the announcement in a statement on Saturday.

The unilateral move came after Russia's defense ministry claimed Ukrainian forces had carried out a drone attack on its Black Sea Fleet in Crimea, with Britain's help.

The statement said the Russian side can no longer guarantee the safety of cargo ships participating in the deal. The ministry cited the attack as the reason.

Russian forces blocked grain exports from Black Sea ports after the invasion of Ukraine began.

The agreement brokered by the United Nations and Turkey in July allowed shipments to resume.

Russia's suspension has raised fears that exports could be disrupted again. This comes amid concerns about a global food crisis.

UN spokesperson Stephane Dujarric says, "It is vital that all parties refrain from any action that would imperil the Black Sea Grain Initiative which is a critical humanitarian effort that is clearly having a positive impact on access to food for millions of people around the world."