Two days after a mysterious fire aboard a Russian submersible killed 14 people, little details have emerged as the Kremlin continued Wednesday to shroud the incident in secrecy.

Speaking at the Russian Navy’s Arctic base of Severomorsk Wednesday, Defense Minister Sergei Shoigu praised the “heroic” crew members that sacrificed their own lives Monday to save a civilian and several other members aboard a deep-sea submersibles that caught fire while on a research mission.

"The submariners acted heroically in the critical situation," he said. "They evacuated a civilian expert from the compartment that was engulfed by fire and shut the door to prevent the fire from spreading further and fought for the ship's survival until the end."

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Shoigu confirmed that 14 seamen were killed and that some members survived, although he did not specify how many. The ministry said the cause of death was intoxication by toxic fumes from the fire.

The ministry has refused to name the vessel involved in Monday’s fatal blaze but has said that the crew were on a research mission to measure sea depths in the Barents Sea.

President Vladimir Putin’s spokesman Dmitry Peskov went a step further in declining to answer questions about the name of the submersible by also refusing to speak about its mission citing confidential information.

"Some information related to the category of state secret", he told reporters. "It is normal practice that such information is not released."

Local media has speculated that the vessel involved was the nuclear-powered AS-12 Losharik, which in itself is a ship that little is known about.

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Having only entered service in 2010, the Losharik is the most advanced and most obscure Russian submarine. It's named after a Soviet-era cartoon character, a toy horse made of small spheres.

In 2012, it was involved in research intended to prove Russia's claim on the vast Arctic seabed. It collected samples from the depth of 8,202 feet, according to official statements at the time. Regular submarines can typically dive to depths of up to 2,000 feet. Some Russian officials have claimed that the sub can travel as deep as 19,685 feet, although this has yet to be independently verified.

The cause of the fire has also remained a mystery after the Ministry strongly denied reports of a “gas explosion” by Norwegian authorities, Reuters reported.

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The Norwegian Radiation and Nuclear Safety Authority said Tuesday that it was informed by Moscow that there was a “gas explosion” aboard a submarine in the Barents Sea but that it did not detect abnormally high levels of radiation, a claim the defense ministry has strongly denied.

The names of the victims have also been withheld. Putin said Tuesday that seven of the dead had the rank of captain and two were awarded the nation's highest medal, the Hero of Russia.

The Associated Press contributed to this report.