Russia's Defence Ministry said on Wednesday it would deem all ships travelling to Ukrainian ports to be potential carriers of military cargo and their flag countries to be parties to the conflict on the Ukrainian side.

The move follows Russia's decision this week to pull out of the U.N.-brokered Black Sea grain export deal which had guaranteed the safety of Ukrainian exports for the past year.

"In connection with the termination of the Black Sea Initiative and the end of the maritime humanitarian corridor, from 00.00 Moscow time on July 20, 2023 (2100 GMT on Wednesday) all ships proceeding to Ukrainian ports in Black Sea waters will be considered as potential carriers of military cargo," the ministry said in a statement on the Telegram messaging app.

Russia was also declaring southeastern and northwestern parts of the Black Sea's international waters to be temporarily unsafe for navigation, it said, without giving details about the parts of the sea which would be affected.

The Turkish- and United Nations-brokered Black Sea grain deal, which was intended to facilitate Russian and Ukrainian agricultural exports, expired on July 17, after Russia declined to renew its participation.

Moscow complains that a parallel deal to ease rules for Russian exports of food and fertiliser were not being implemented. Kyiv has called for security guarantees to allow shipping to resume without Russian participation.

(Reporting by Felix Light; Editing by Peter Graff)