ISTANBUL

The Swedish Coast Guard boarded a suspected "shadow fleet" oil tanker in the Baltic Sea near the southern port city of Trelleborg, authorities said Friday.

The operation targeted the Sea Owl 1, a 228-meter tanker sailing under the Comoros flag that was suspected of operating under a false flag while on the EU sanctions list, Swedish news broadcaster SVT reported.

The Swedish Coast Guard said the vessel was boarded on Thursday evening outside Trelleborg with the assistance of the police and the national task force.

According to senior prosecutor Adrien Combier-Hogg, the ship's commander, a Russian national, is suspected of several crimes.

“The suspect is the commander on board the ship Sea Owl 1 and a Russian citizen,” Combier-Hogg said in a statement, adding that the investigation concerns suspicions of using false documents and additional violations of maritime law.

He said authorities are conducting an “intensive investigation,” including searches on board the vessel, interrogations, and examinations of suspected forged documents.

Swedish Coast Guard press officer Mattias Lindholm said the tanker had been heading toward Russia.

“Our overall assessment is that the risk of safety deficiencies on board is high,” said Daniel Stenling, deputy chief of operations at the Coast Guard.

Authorities said the operation involved the Coast Guard’s boarding team, the police’s national task force, and a police helicopter.

On March 6, Swedish authorities also took control of another tanker, the Caffa, outside Trelleborg. Its captain is suspected of similar violations of maritime regulations and the use of false documents, and the vessel has since been placed under an international usage ban by the Swedish Transport Agency.