Reports indicate that Russia has suspended participation in a deal to export agricultural produce from Ukrainian ports brokered by the United Nations and Türkiye, following attacks on ships in Crimea, TASS quoted the Russian defense ministry as saying on Saturday.

Russia said that Ukrainian forces, with the help of drones, attacked ships from the Black Sea Fleet in Sevastopol, the biggest city in Russian-annexed Crimea, in the early hours of Saturday.

"Taking into account... the terrorist act by the Kyiv regime with the participation of British experts against the ships of the Black Sea Fleet and civilian vessels involved in ensuring the security of the 'grain corridor,' the Russian side suspends participation in the implementation of agreements on the export of agricultural products from Ukrainian ports," the ministry said in a statement.

The ministry said earlier that the drone attacks on Saturday were largely repelled, with minor damage to a Russian minesweeper.

The U.N. is in contact with Russian authorities following the reports of suspension, a U.N. spokesperson said on Saturday.

"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," U.N. spokesperson Stephane Dujarric said.

U.N. aid chief Martin Griffiths had said only on Wednesday that he was "relatively optimistic" that the deal that allowed a resumption of Ukraine Black Sea grain exports would be extended beyond mid-November.

Türkiye, the U.N., Russia and Ukraine signed an agreement in Istanbul on July 22 to resume grain exports from three Ukrainian Black Sea ports, which paused after the start of the Russia-Ukraine war in February.

Under the July 22 agreement, Ukraine was able to restart its Black Sea grain and fertilizer exports, which had stalled when Russia invaded its neighbor on Feb. 24. The Ukraine export deal was initially agreed for 120 days.