"The Russian Federal Security Service detained five members of the Daesh terrorist cell, who had been plotting terrorist acts on the territory of a number of Russian regions," the FSB's public relations center said.
The FSB went on to say that the communications between terrorists were maintained via the Telegram messenger, including from abroad.
"During the searches, we confiscated an arsenal of improvised explosive devices, explosives, firearms and ammunition from the detainees," the FSB stated.
Earlier in the day, the agency informed of the elimination of two leaders of a religious extremist sect in Nevinnomyssk in the Stavropol region in the country's south. According to the security service, they have also found a laboratory for the production of explosives, guns, munitions and grenades at the site.