Russia said on Monday that it would be ready to consider rejoining the Black Sea grain export deal if it saw "concrete results," but that so far its demands had not been met.

The Russian foreign ministry said in a statement that, despite United Nations efforts to prolong the deal, obstacles to Russian food and fertilizer exports remained.

"Only upon receipt of concrete results, and not promises and assurances, will Russia be ready to consider restoring the deal," it said.