MOSCOW (AP) — Russia's top domestic security agency says it has busted up a sleeper cell of the Islamic State group that plotted terror attacks in the Russian capital.

The Federal Security Service (FSB) says it has arrested six suspected members of the IS cell in the Moscow region. It added that they have received orders from citizens of Central Asian nations in Syria.

The agency said Friday the suspects plotted terror attacks in Moscow with self-made explosives and firearms. FSB said automatic weapons and plans for attacks were found during a search.

The Russian government and military have waged a campaign in support of Syrian President Bashar Assad since 2015, while thousands of Russian citizens and people from other ex-Soviet nations have traveled to Syria to join IS.