BEIRUT, March 23 — The Islamic State (IS) jihadist group said Saturday four of its militants carried out an attack on a concert hall in a Moscow suburb that Russian authorities said killed at least 133 people.

"The attack was carried out by four IS fighters armed with machine guns, a pistol, knives and firebombs,” IS said on one of its Telegram channels.

The militant group said its fighters killed "dozens of Christians” as part of its "raging war” with countries it said were fighting Islam.

The jihadists had already said on Friday night they carried out the attack, and claimed their fighters had "returned to base safely”.

The Kremlin, which has not reacted to the militant group’s claim, said 11 people had been arrested "including four terrorists” involved in the attack.

Russian officials have suggested the attackers had links to Ukraine, a claim labelled as "absurd” by Kyiv.

Russia is fighting IS in Syria and the jihadist group has also had a presence in the Muslim-majority Russian republics of Ingushetia, Dagestan and Chechnya.

The group has carried out attacks in Russia but has never before said it was behind such a major atrocity. — AFP