Ukraine on Wednesday said it struck a Russian naval transport vessel docked in the Azov Sea near the besieged port city of Mariupol, a month into the Russian invasion.

"The Orsk large landing ship of the Black Sea Fleet of the occupiers has been destroyed in the port of Berdyansk captured by Russia," the Ukrainian Navy wrote on social media.

Plumes of black smoke billowed from a large gray vessel docked next to big cranes in amateur footage of what the Ukrainian Navy said was the strike on the ship.

There was no immediate response to the claim from Russia's Defense Ministry and Agence France-Presse (AFP) could not independently confirm the strikes.

Russia's state-run Tass news agency earlier this week had described the arrival of landing craft as "an epic event" that "opens up opportunities for the Black Sea in terms of logistics," citing the Russian Defense Ministry-linked television channel, Zvezda.

Tass reported that the vessel was capable of carrying up to 1,500 tons of cargo.

Berdyansk is situated around 80 kilometers (60 miles) to the west of the strategic city of Mariupol, which has been encircled and heavily damaged by Russian forces.

Thousands of civilians have escaped Mariupol through evacuation corridors but some 100,000 people remain lacking water and electricity.

Kyiv says more than 2,500 people have been killed in the city since Russian President Vladimir Putin launched his invasion of Ukraine one month ago.

Russian forces have advanced further in southern Ukraine but only control Kherson, a town of approximately 200,000 people.