The Losharik is one the Russian navy's most secretive vessels and details about its design are hazy. The Russian leader, who is also commander-in-chief of the country's armed forces, ordered him to draw up proposals to posthumously grant those who were killed state awards.
The Washington Times reported that the secret Losharik submarine may be involved in Moscow's effort to tap into or sever some of the 550,000 miles of underwater fiber-optic cables that span the Atlantic and Arctic sea lanes.
But unlike NR-1 that was created to dive to 910 meters (3,000 feet), the Losharik was built to go far deeper.
The Ministry of Defense didn't report the incident until the day after it happened.
There are no confirmed reports as of yet that of a link between the events.
"It belongs to the highest level of classified data, so it is absolutely normal for it not to be disclosed", Peskov said. The submarine is also operated by GUGI.
Russian President Vladimir Putin on Wednesday signed into law a bill on the suspension of a crucial arms control treaty signed by USA president Ronald Reagan and Soviet leader Mikhail Gorbachev.
Two days after the tragedy the defence ministry described the victims as "true patriots" and top professionals, adding they repeatedly took part in expeditions to study the Arctic and plunged to "maximum depths".
"There has not been any formal communication from Russian Federation to us about this", Per Strand, a director at the Norwegian Radiation and Nuclear Safety Authority, told Reuters news agency when asked if it had been informed that the submarine was nuclear-powered.
USA defence chiefs have however branded it a "sabotage vessel" capable of cutting underwater cables.
The governor of Saint Petersburg, Alexander Beglov said Wednesday that the crew was based in the city.
Russian media have previously reported, without official confirmation, that the vessel was designated as either AS-31 or AS-12 and is created to carry out special operations at depths where regular submarines can not operate.
Putin has said that the submarine was manned by an elite and senior crew, two of whom already held the Hero of Russian Federation title before their deadly mission. But he didn't say how many crew members were actually on the vessel during the fire.
"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".
He said that all the dead would be nominated for state honors and that their families would receive all necessary support.
The Russian Defense Ministry later Wednesday released the names of those who died on the vessel, identifying them as 1st Rank Captains Denis Dolonskiy, Nikolai Filin, Vladimir Abankin, Andrei Voskresenskiy, Konstantin Ivanov, Denis Oparin, Konstantin Somov, 2nd Rank Captains Aleksander Avdonin, Sergei Danilchenko, Dmitri Soloviev, Lieutenant Colonel Alexander Vasilyev, 3rd Rank Captains Viktor Kuzmin, Vladimir Sukhinichev and Captain Lieutenant Mikhail Dubkov.