Muslim? Chechnya was the place where Muslims held children hostage in a school....
Technically, Beslan is in North Ossetia, but the attack was conducted by Muslim terrorists mostly from Chechnya and Ingushetia. That whole area has been a war zone between Russia/the USSR and the Ottomans and Muslim locals well back into the days of the Tsars.
Chechen Muslim terrorists have been capable of atrocities that I’m not even sure some Palestinians could pull off. Things like Beslan and the Moscow theater siege. They have a particular specialty of using female suicide bombers, they have used those to bring down at least two Russian aircraft in-flight.
Beslan school massacre.