More than 20 people have died and 21 have been injured in an incident on a Russian nuclear submarine, Russian Pacific Fleet spokesman Igor Dygalo reported. Twenty-one injured people have been evacuated from the submarine. There were 2-8 people on board at the time of the incident, 81 of whom were servicemen. At the moment the submarine is returning to the port in the far eastern Primorsky territory. According to preliminary investigations, the incident was caused by the failure of the submarine’s fire extinguishing system during the trials. The ship itself had not been damaged and there had been no radiation leaks. Russian President Dmitry Medvedev has ordered Defense Minister Anatoly Serdyukov to thoroughly investigate the incident and provide all necessary support to the families of the dead. A group of officers from the Russian Chief Military Prosecutor’s Office are flying to the scene of the incident.