MOSCOW, March 7 (RIA Novosti) – The police and the Federal Security Service (FSB) have uncovered an underground arms factory and large cache of firearms in the Moscow Region, the Interior Ministry reported on Thursday.

“Two underground workshops for arms re-engineering were liquidated and four suspected criminal gang members were arrested,” the police reported in a statement.

The workshops were based in two garages west of Moscow, where the security forces discovered at least nine machine tools for arms production, repair, modernization and reengineering.

The police also found at least 20 weapons, including World War II machine-guns, rifles and submachine-guns and a Kedr submachine-gun with a silencer, as well as parts for mines, grenades and hundreds of ammunition, they said.

The suspected criminals were repairing the old weapons and reactivating deactivated modern ones for sale, the police said.