The Defense Ministry said on July 20 that from midnight of July 21, all vessels on the Black Sea heading toward Russian or Russia-occupied ports will be treated as carrying military cargo "with all associated risks."
"The Russian Federation has once again brutally violated the universal right to free navigation for the whole world and is deliberately undermining food security, condemning millions of people to starvation," the statement said.
The ministry noted that the Kremlin has turned the Black Sea into a danger zone by threatening civilian vessels and trade routes and attacking civilian infrastructure in cities.
"In addition, navigation in the areas of the northeastern part of the Black Sea and the Kerch-Yenikale Strait of Ukraine is prohibited as dangerous since 5 a.m. on July 20, 2023," Ukrainian officials announced.
Shortly after withdrawing from the Black Sea Grain Initiative on July 17, Russia declared that as of July 20, all vessels sailing to Ukrainian ports will be considered "potential carriers of military cargo" and therefore legitimate targets.
According to the U.K. Defense Ministry, the Russian Black Sea Fleet will likely be imposing the blockade, but at the risk of attacks by Ukrainian surface drones and cruise missiles.
"The fate of the cruiser Moskva proves that the Defense Forces of Ukraine have the necessary means to repel Russian aggression at sea," Ukraine's defense ministry noted.
According to the White House, the Kremlin is considering attacking civilian vessels on the Black Sea and then putting the blame on Ukraine. U.S. National Security Council spokesperson Adam Hodge said that Russian forces laid additional sea mines in approaches toward Ukrainian ports.
Russia's withdrawal from the grain deal sparked international condemnation and fears of rising food prices. The agreement, brokered by Turkey and the U.N. in July 2022, allowed Ukraine to export its agricultural products during the ongoing full-scale Russian invasion.
Following the termination of the agreement, Russia launched three consecutive strikes over the past three days against Odesa, damaging the port infrastructure and destroying 60,000 tons of grain.