Russia suspended participation in the U.N.-brokered deal on Saturday after what it said was an attack on vessels from its Black Sea fleet.

    Moscow resumed its participation on Wednesday, with the Russian defence ministry saying it had received guarantees from Ukraine that it would not use the Black Sea grain corridor for military operations against Russia.

    In a statement on Facebook, Ukrainian Foreign Ministry spokesman Oleg Nikolenko made clear Kyiv had offered nothing new to Russia to ensure it returned to the deal, intended to free up Ukrainian grain exports following Russia's Feb. 24 invasion.

    "Our state has not undertaken any new commitments that go beyond those already existing in the grain agreement," he said.

    "Recall that within this agreement (in July) the parties committed to guarantee a safe and reliable functioning environment for the grain corridor. Ukraine has never put a grain route in danger."

    He said Ukraine was clearly adhering to the terms of the agreement.

    "Ukraine did not use and did not plan to use the grain corridor for military purposes," he said.

    "Moscow has returned to the grain deal thanks to the active diplomacy of U.N. Secretary-General Antonio Guterres and Turkish President Recep Tayyip Erdogan. In coordination with Ukraine, they found words that (Russian President Vladimir) Putin understood. It was a position of strength, not a deed."