April 3 (UPI) — The Swedish Coast Guard boarded a ship Friday that was sanctioned by the European Union, alleging the ship committed an environmental crime for an oil spill off the coast.

The ship is suspected of an about 7-mile oil spill Thursday in the Baltic Sea, east of Gotland, an island off the east coast of Sweden.

The coast guard said it was found that the ship, the Flora 1, was sanctioned and that it had flown under several flags. It was en route from a port in the Gulf of Finland with a destination of Santos, Brazil. It was carrying oil, and there were 24 crew members on board.

The ship is now anchored south of Ystad, Sweden, off the southern coast. The coast guard and the Swedish police are conducting the investigation.

“The Baltic Sea is an extremely sensitive ecosystem, and there is zero tolerance for emissions,” the coast guard said. “Intervening against ships that pollute is part of the Coast Guard’s everyday work.”

Russia operates a “shadow fleet” of ships that are used to avoid sanctions. They are usually old ships in poor condition, unknown ownership and without insurance, Euro News reported.

“The government takes this incident seriously, even though it does not involve a major oil spill this time,” Civil Defense Minister Carl-Oskar Bohlin said on X. The shadow fleet “poses a significant safety and environmental threat.”

“A more extensive spill could have had devastating consequences for marine ecosystems and the Swedish coastline,” Bohlin added.