MOSCOW (AP) — Russia's top domestic security agency said Friday it has detained a group of suspects accused of planning firebomb attacks on official buildings.

The Federal Security Service, or FSB, the main KGB successor agency, said the suspects detained in the Moscow region were planning to hurl firebombs at administrative buildings and attack police over the weekend in order to provoke mass riots.

It said the suspects belonged to the Artpodgotovka (Artillery Bombardment) group founded by opposition activist Vyacheslav Maltsev and were aiming to "destabilize socio-political situation in the country."

The FSB said it also has stopped the activities of Maltsev's group in the cities of Krasnoyarsk, Krasnodar, Kazan, Samar and Saratov — the major provincial centers.

Maltsev, who described himself as a nationalist and anarchist, has said on YouTube that Russia is up for a revolution this weekend just as the nation prepares to mark the centennial of the 1917 Bolshevik revolution on Nov. 7.

Maltsev, a former regional legislator from Saratov, unsuccessfully ran for the federal parliament in 2016. He left Russia during the summer, and in October was arrested in absentia on extremism charges.