Britain's defense ministry says Russia has deployed a state-of-the-art naval vessel to the southern Black Sea, which could possibly disrupt shipping there.

In its intelligence update on Wednesday, the ministry said a modern corvette, the Sergey Kotov, has deployed to the area. This follows Russia's withdrawal from a deal allowing grain exports from Ukrainian ports.

The ministry said the Russian vessel is patrolling the shipping lane between the Bosphorus Strait and Odesa. It said it's possible it will form part of a task group to intercept commercial vessels Russia believes are heading to Ukraine.

The ministry said "there is now the potential for the intensity and scope of violence in the area to increase."

Meanwhile, the governor of the eastern Ukrainian region of Donetsk said on Wednesday a Russian missile attack killed two civilians and injured two others.

The governor of the southern Kherson region also said that Russian shelling left two people dead and three others injured.

Ukraine's General Staff of the Armed Forces said on Wednesday Ukrainian forces repelled Russian attacks in Donetsk, and stopped Russia's advance in the region of Zaporizhzhia and elsewhere.

The United States on Tuesday announced additional military aid worth up to 400 million dollars to support Ukraine's counteroffensive against Russia.

The aid package includes additional munitions for air defense systems.