Russia's FSB security service said on Monday it had arrested seven Islamic State militants in the Urals city of Yekaterinburg who it said had been planning bomb attacks in Moscow, St Petersburg and the Sverdlovsk region.

The group included Russian nationals and citizens of Central Asian states, the FSB said in a statement, saying it had charged the group with terrorism, and the illegal possession of weapons and explosives.

It said it had uncovered a bomb-making laboratory during searches of the suspects' homes and had found detonators, guns, grenades and extremist literature.

"It was established that after the terror acts, those detained plan to leave for Syria to take part in military action in the ranks of Islamic State," the FSB said.

The group had been led by an Islamic State fighter who had arrived from Turkey, the FSB said, giving no further detail.