The Moscow theater hostage crisis, also known as the 2002 Nord-Ost siege, was the seizure of the crowded Dubrovka Theater in Moscow by Chechen terrorists on 23 October 2002, resulting in the taking of 912 hostages. The attackers, led by Movsar Barayev, claimed allegiance to the Islamist separatist movement in Chechnya. They demanded the withdrawal of Russian forces from Chechnya and an end to the Second Chechen War. The crisis was resolved when Russian security services released sleeping gas into the building, and subsequently stormed it, killing all 40 hostage takers. 132 hostages died, largely due to the effects of the gas.