MOSCOW, May 25 (Xinhua) -- The Russian Federal Security Service (FSB) said on Thursday it had detained four suspected members of a terrorist group, which planned to attack Moscow's transport infrastructure.
The detainees were holders of Russian and Central Asian passports, and they received instructions from the Islamic State (IS) terrorist group operating in Syria, the FSB said in a statement.
After committing sabotage and terrorist attacks, the suspects planned to go to Syria to take part in the hostilities there, the FSB said.
The FSB carried out searches, discovering a laboratory for the production of explosives, and seized an improvised explosive device, as well as automatic firearms, ammunition, grenades, literature and video recordings of extremists and terrorists, it said.
FSB Director Alexander Bortnikov said last month that the IS might plot terrorist attacks in Russia.
He said the FSB needed to improve work aimed at preventing such incidents as the April 3 terrorist attack in Russia's second largest city of St. Petersburg, which killed 14 people and injured dozens of others.
Prior to Thursday's detention, ten people suspected of participating in terrorist cells were detained in the course of the investigation of the St. Petersburg attack and a large number of arms and explosives were seized.