The Swedish Coast Guard has detained the tanker Flora 1, part of Russia’s so-called “shadow fleet,” on suspicion of causing an oil spill in the Baltic Sea east of Gotland Island, the agency’s press service reported on Friday, April 3.

This is the first such case in the region where a vessel has been detained on suspicion of an environmental crime.

An oil slick approximately 12 km long was discovered on the morning of April 2 by a Swedish Coast Guard aircraft, and suspicion soon fell on the tanker Flora 1. Swedish prosecutors have launched a preliminary investigation. The vessel, loaded with oil, has 24 crew members on board.

According to the Automatic Identification System (AIS), during the night of April 2 the tanker made a sharp turn toward territorial waters near Kaliningrad before returning to international waters. The ship had departed from a port in the Gulf of Finland, and its final destination remains unknown.

According to Ukrainian intelligence, Flora 1 had previously repeatedly switched off its identification system and carried out ship-to-ship oil transfers near Greece. The vessel is affiliated with the Indian company Gatik Ship Management, one of the key operators of the “shadow fleet” used to transport Russian oil under Western sanctions, and is also linked to Galena Ship Management.

A number of countries and organizations have imposed sanctions on Flora 1: the United Kingdom since February 2025, Canada and Australia since June 2025, and the European Union since July 2025. Later, Switzerland, New Zealand, and Ukraine also introduced restrictions. On February 21, 2026, Ukraine additionally sanctioned the vessel’s captain.