Fourteen people have died after a fire on a Russian naval deepwater research submarine in what is being described as one of the worst naval disasters in post-Soviet Russia.

The fire occurred when the submersible was undertaking research in the country’s northern territorial waters, the Russian defence ministry stated.

Russian media sources, including Russian media outlet RBC, identified the vessel as the Losharik, an advanced nuclear-powered submersible capable of performing special missions at great depths.

Following the incident, Russian President Vladimir Putin met Defence Minister Sergei Shoigu to take stock of the situation.

Putin was quoted by Reuters as saying: “This is a great loss for the navy. We express our deepest condolences to the families of those who died. We will do everything we can to support them.”

An investigation has been launched into the fire accident to determine the cause.

According to preliminary information from news agencies, the vessel was performing a military survey on behalf of the navy.

Among the deceased sailors, seven held the rank of captain and two were recipients of the nation’s highest medal, the Hero of Russia.

The 14 crew members are believed to have died due to inhalation of poisonous gases caused by the fire.

Interfax news agency cited a ministry statement as saying: “Fire broke out on-board a deep-water scientific research vessel that was studying the marine environment of the world ocean on behalf of the Russian Navy. Fourteen submariners died as the result of smoke inhalation.”

Losharik was brought to Severomorsk, the main base of Russia’s Northern Fleet, after the fire was put out.

In 2000, Russia’s nuclear-powered submarine Kursk sank in the Barents Sea following an explosion. All 118 members on the submarine also died.

More recently, 20 people died of asphyxiation when the Russian submarine K-152 Nerpa was involved in an accident during sea trials.

The incident occurred when a firefighting system was accidentally set-off.