A Russian-flagged liquefied natural gas tanker sank in the Mediterranean Sea after a series of explosions triggered a massive fire off the Libyan coast, authorities said on Wednesday. All 30 crew members were rescued and no casualties were reported.

Libyan port officials said the vessel, the Arctic Metagaz, experienced "sudden explosions" on Tuesday night while sailing roughly 240 kilometres north of the coastal city of Sirte. The blasts were followed by a fire that engulfed the ship before it eventually went down between Libya and Malta.

Russia accused Ukraine of carrying out the attack using naval drones launched from the Libyan coast. Moscow's transport ministry described the incident as "an act of international terrorism and maritime piracy," alleging that Ukrainian unmanned vessels were responsible for striking the tanker. Kyiv did not immediately comment on the claim.

The Arctic Metagaz was transporting approximately 61,000 tonnes of liquefied natural gas at the time of the incident. According to Libyan maritime authorities, the entire crew was evacuated safely and transferred to another vessel heading towards Benghazi.

The tanker had departed from Murmansk, in northwestern Russia on the Barents Sea, and was reportedly en route to Port Said in Egypt. Ship-tracking data indicated that its last recorded position placed it in the central Mediterranean, off Malta's coast.

The vessel was believed to be operating under Western sanctions, amid suspicions that it formed part of Russia's so-called "shadow fleet" - a network of energy tankers accused of circumventing international restrictions imposed following Moscow's invasion of Ukraine. The precise cause of the explosions has not been independently confirmed.

The incident adds to rising maritime tensions linked to the war in Ukraine and highlights the vulnerability of commercial shipping routes in the Mediterranean region.