MOSCOW • Russia's intelligence agency says it has arrested members of a "cell" of the Islamic State in Iraq and Syria (ISIS) which was preparing terror attacks.

The FSB said in a statement yesterday that it had "thwarted the illegal activities of... the international terrorist organisation ISIS" last Saturday, by detaining all members of a cell in the Moscow region.

It said they were all from Muslim-majority republics in the Caucasus but took orders from "foreign emissaries" pledging allegiance to ISIS.

An FSB representative later told Russian media that two of the men were brothers from Russia's Republic of Dagestan, in the north Caucasus. "One is 22 years old, the other is 19," the FSB employee said.

The group was planning "significant" terror acts in Russia, including in densely populated places and on public transport, the statement said, without specifying the number held.

Two homemade explosives as well as guns and grenades were found during raids on their homes.

Russian officials regularly claim to have foiled terror plots.

In August, the FSB said it had arrested four ISIS members who were planning suicide attacks in Moscow shopping malls.

In July, security services said they had arrested seven Central Asian migrants accused of preparing attacks in St Petersburg, where 15 were killed in a metro bombing in April claimed by little-known group Imam Shamil Battalion.

AGENCE FRANCE-PRESSE