Russia's state security service says it has charged seven people with terrorism in the country's Ural mountain region.

The local security services said on Wednesday that the suspects, who were originally detained on Feb. 8, have been officially charged with terrorism. Authorities believed the group was plotting to carry out terrorist acts in Moscow, St. Petersburg and the regional capital, Ekaterinburg.

Previously, law enforcement officials said they uncovered the group's laboratory for manufacturing explosives.

The accused are said to be both Russian citizens and citizens of Central Asian countries; their leader is reported to be a member of the Islamic State group who transited to Russia via Turkey, according to the local security services.

State authorities estimate that more than 3,000 Russians are fighting in Central Asia.