Cairo. A Russian-flagged tanker carrying liquefied natural gas exploded and erupted in flames before sinking in the Mediterranean Sea off the coast of Libya, authorities in the North African country said Wednesday. No casualties were reported.

The tanker was under Western sanctions, suspected to be part of Russia’s shadow fleet of energy tankers trying to bypass sanctions imposed on Moscow over its war in Ukraine. The cause of the explosion was not immediately clear.

According to the Libyan Maritime Authority, there was a “sudden explosion, followed by a massive fire” on the Arctic Metagaz on Tuesday while the LNG carrier was about 240 kilometers (150 miles) off the coast of the Libyan city of Sirte.

The tanker, carrying 61,000 tons of LNG, “completely sank” between Libya and Malta, a statement said. All 30 crew members were rescued and put on another vessel heading to the Libyan city of Benghazi, it said.

The Metagaz had sailed from the northwestern Russian city of Murmansk on the Barents Sea and was bound for Port Said in Egypt, on the Mediterranean, it said. Its last reported position was in the western Mediterranean off the coast of Malta, according to MarineTraffic, a ship-tracking platform.