MOSCOW, Russia (AFP) — Ukraine's maritime grain exports were halted Sunday after Russia suspended its participation in a landmark agreement that allowed the vital shipments, blaming drone attacks on its ships in Crimea.

The July deal to unlock grain exports signed between Russia and Ukraine and brokered by Turkey and the United Nations, is critical to easing the global food crisis caused by the conflict.

The agreement had already allowed more than nine million tons of Ukrainian grain to be exported and was due to be renewed on 19 November.

On Saturday, Russia said it was halting its participation after its army accused Kyiv of a "massive" drone attack on its Black Sea fleet, which Ukraine labeled a "false pretext."

Sevastopol in Moscow-annexed Crimea has been targeted several times in recent months and serves as the headquarters for the Black Sea fleet and a logistical hub for operations in Ukraine.

The Russian army claimed to have "destroyed" nine aerial drones and seven maritime ones in an attack on the port early Saturday.

"In light of the terrorist act carried out by the Kyiv regime with the participation of British experts against ships of the Black Sea fleet and civilian vessels involved in the security of grain corridors, Russia suspends its participation in the implementation of the agreement on the export of agricultural products from Ukrainian ports," the Russian defense ministry said on Telegram.

The center coordinating the logistics of the deal or JCC said in a statement that no traffic was planned for Sunday.

"A joint agreement has not been reached at the JCC for the movement of inbound and outbound vessels on 30 October," it said. "There are more than ten vessels both outbound and inbound waiting to enter the corridor."

Ukrainian President Volodymyr Zelensky called the Russian move "an absolutely transparent intention of Russia to return the threat of large-scale famine to Africa and Asia."