MOSCOW (AP) — A crew member who went missing during a fire on Russia’s only aircraft carrier was found dead Friday, raising the death toll from the blaze to two, the nation’s military officials said Friday.

The fire on the Admiral Kuznetsov broke out during welding work at a shipyard in the Arctic port of Murmansk on Thursday and spread quickly through the carrier’s internal compartments. The ship’s crew and emergency teams spent more than 20 hours battling the blaze.

The military reported two crew members dead, and authorities in Murmansk said 11 other people were injured.

The Investigative Committee, Russia’s top state investigative agency, opened a probe into a possible violation of safety rules.

The Admiral Kuznetsov has been plagued by breakdowns and setbacks since its launch in 1985. The massive blaze follows a 70-ton crane crashing onto the Admiral Kuznetsov’s deck in October 2018, when a mammoth floating dock holding the ship sank.

The crane left a hole of 20 square meters (215 square feet), and the loss of the dock significantly slowed down repairs on the carrier since the navy lacked another of comparable size.

The fire will further push back the work to fit the ship with modern control systems and new weapons.

In 2016, the Admiral Kuznetsov was deployed to the eastern Mediterranean as part of Russia’s campaign in Syria, launching the first carrier-mounted attacks in Russian naval history.

It lost two carrier-borne fighters during the Syria mission.