According to Ukrainian officials, a Russian landing ship was destroyed and two other boats were damaged in the occupied Ukrainian port city of Berdyansk. The Ukrainian military released footage early Thursday, claiming that its forces had attacked the Orsk.
The cause of the explosion and fire on board the ship is unknown.
Berdyansk, located west of Mariupol, was captured four days after Russia invaded Ukraine. Russia claims to have used the port as a base to transport equipment for its troops.
The arrival of the Orsk in Berdyansk last week was hailed as a “epic event” by Russian army TV because it was the first Russian warship to dock there.
Murad Gazdiev, a Russian state TV reporter, captured drone footage of an armored personnel carrier being offloaded from the Orsk in the port. The armoured vehicles were to be used to reinforce Russian troops, according to the TV report.
At 07:00 (05:00GMT) on Thursday, video posted by the navy and on social media showed explosions and a large ship on fire at the port.
According to Deputy Defence Minister Hanna Malyar, the military hit a “huge target” capable of carrying 20 tanks, 45 armored vehicles, and 400 troops.
The Orsk was the first Russian warship to enter Berdyansk, which is about 80 kilometres (50 miles) west of Mariupol, which is under siege and has been heavily shelled.
If the Orsk was hit, it would be yet another major setback for Russian troops who have already suffered heavy losses in the conflict. Between 7,000 and 15,000 soldiers have been killed, according to NATO, including at least six generals, though Moscow has only acknowledged one.
According to Russian state media website RIA-Novosti, citing Russian defence ministry spokesman Igor Konashenkov, Russia has claimed to have occupied the city of Izyum in the Kharkiv region of eastern Ukraine.
Berdyansk is strategically important to Russia because it lies halfway between Crimea and the besieged city of Mariupol, some 80 kilometers (50 miles) to the east, where an estimated 100,000 people are stranded and facing Russian bombardment.
Some of those who managed to flee Mariupol have arrived in Berdyansk, where they will be taken inland to Zaporizhzhia, according to Ukraine’s deputy prime minister.
The capture of Berdyansk and Melitopol is part of Russia’s plan to build a land bridge connecting Crimea and the Russian border, as well as a route to Zaporizhzhia.