Russia will regard all ships sailing in the waters of the Black Sea to Ukrainian ports as "potential carriers of military cargo," the Russian Defense Ministry said in a statement on Wednesday.

"Due to the termination of the Black Sea Initiative and the curtailment of the maritime humanitarian corridor, all ships en route to Ukrainian ports in the Black Sea will be considered potential carriers of military cargo from 00:00 Moscow time on July 20, 2023," it said.

The ministry said countries whose flags are present on those vessels would be viewed as parties to the conflict from the Ukrainian side.

It also temporarily declared several areas in the northwestern and southeastern parts of the international waters of the Black Sea "dangerous for navigation."

Russia and Ukraine signed with Türkiye and the United Nations Black Sea Grain Initiative separately in Istanbul in July 2022 to allow Ukraine to export its grain and other agricultural products through its Black Sea ports.

Moscow suspended its participation in the agreement on July 17, 2023 when the deal was set to expire, saying it would return to the deal as soon as Russia's part of the agreement is fulfilled.

Ukraine stated that it hopes to continue the deal after Russia's withdrawal. But Russia's suspension has caused concerns worldwide. 

UN Secretary-General Antonio Guterres "will continue to explore all possible avenues to ensure that Ukrainian grain, Russian grain, Russian fertilizer are out on the global market," UN spokesperson Stephane Dujarric said on Tuesday.

Analysts warned that the collapse of the Black Sea export corridor would create market tension and push up food prices over the medium term.

Read more:

Black Sea grain deal: How the collapse could impact the world

(With input from Xinhua)