MOSCOW, April 27 (Xinhua) -- Russia's Federal Security Service (FSB) said Friday it had an operation together with the Interior Ministry, destroying a major network that trafficked drugs from European Union (EU) countries to Russia.

The cross-border ring delivered narcotic drugs and psychotropic substances "on an especially large scale" from EU to Russia and sold them in the country's Northwestern Federal District, the FSB said in a statement.

It said six active members of the gang -- all Russian citizens -- were caught red-handed in St. Petersburg and Leningrad Region. A large amount of drugs of various types as well as firearms and ammunition were seized.

The Interior Ministry's Investigation Department has launched two criminal cases against the detainees.