PARIS: French President Emmanuel Macron said Wednesday that an oil tanker immobilized off the French Atlantic coast had committed “very serious wrongdoings” and linked it to Russia’s shadow fleet, which is avoiding Western sanctions over Moscow’s war in Ukraine.

The tanker was sailing last week off the coast of Denmark and was cited by European naval experts as possibly being involved in drone flights over the country.

French naval forces forcibly boarded the ship a few days ago at the request of prosecutors who suspected wrongdoing, a military official said Wednesday. The prosecutor’s office in the western French city of Brest said a judicial investigation has been opened into the crew’s “refusal to cooperate” and “failure to justify the nationality of the vessel.”

The ship was ordered to stay in place pending further investigation, the military official said. French naval forces boarded the ship again Wednesday to provide food and fuel to the crew aboard, according to the official, who was not authorized to be publicly named discussing an ongoing investigation.

The ship left the Russian oil terminal in Primorsk near Saint Petersburg on Sept. 20, sailed off the coast of Denmark and has stayed off the coast of the French western port of Saint-Nazaire since Sunday, according to the Marine Traffic monitoring website.