Police have found explosives, detonators and a gun in a cinema in St Petersburg that was closed for renovation, the Interior Ministry said today.
Interfax news agency quoted a ministry spokesman as saying the stash included two pounds of plastic explosives, a stick of dynamite, two improvised explosive devices, a hunting rifle and 23 rounds.
Interfax reported that prior to the discovery, police had arrested three men from Kazakhstan and confiscated four Kalashnikov assault rifles from them.
Interfax said the arrests had been made by organised-crime squad detectives, suggesting the find might have been linked to criminal gangs. The Interior Ministry was not immediately available for comment.
Russia has been on a high state of alert following a wave of attacks blamed by authorities on Chechen separatists, including last week's school hostage drama in which at least 326 died, two plane crashes caused by bombs and a Moscow suicide bombing.