A Serbian-owned ship carrying 1,500 tons of coal from Russia sank in the Romanian port of Constanta, the tylaz.net portal reported on Wednesday.

The portal said that the ship was loaded in the port and was meant to join a convoy bound for the Danube-Black Sea canal when it started taking on water and sank. “The 1,500 tons of coal belonged to the Russian Federation and were to reach Serbia,” it said.

The Serbian power company (EPS) issued a statement saying that the coal that sank in Romania was not intended for its power plants.

“The Romanian Naval Authority ordered an investigation into the cause of the sinking,” the portal said.

The Digi24 Romanian-language portal said that the ship was registered in Germany and had a Serbian owner.