MOSCOW, Jan. 10 (Xinhua) -- The Russian Federal Security Service (FSB) said Thursday it had seized 43 kg of heroin in a recent operation.

During the operation, FSB officers detained active members of a cross-border criminal group while they were transferring drugs in a forest in Moscow at night.

The FSB said that, through the operation, it curbed a channel for smuggling drugs from Central Asian countries to Russia.

The FSB said the detainees are citizens of several countries, but did not provide further details.