The breaking news has now been expanded to include:
Submarine Explosion"Blast damages Russian submarine
An explosion has damaged a Russian naval submarine undergoing repairs in the Arctic, but there are no reports of any casualties, Russian media say.
Officials have not specified whether the submarine is nuclear-powered.
The background radiation level is normal in Severodvinsk, where the incident took place on Thursday, Interfax news agency reports.
The explosion damaged more than 20sq m (215sq ft) of the submarine's hull, Ekho Moskvy radio reports."