This highly autonomous, small (probably only 20 to 50 members at any given time) group was first founded and led by Shamil Basayev under the name of Riyadus Salihiin Reconnaissance and Sabotage Battalion of Chechen Martyrs (later also known as Islamic Brigade of Shaheeds) in October 1999 as a "special battalion to carry out acts of sabotage" in retaliation for the Grozny missile attack. Basayev took responsibility for a series of suicide attacks in Chechnya and Russia, including the truck bombing which destroyed the Chechen Republic's government headquarters in Grozny and killed over 80 in 2002, the truck bomb attack at Chechnya's FSB headquarters in Znamenskoye which killed more than 50 in 2003, the truck bomb attack at a Russian military hospital in Mozdok, North Ossetia, which killed at least 50 the same year, and a series of "Operation Boomerang" suicide bombings (many of them conducted by women) which have killed over 200 civilians in Moscow and elsewhere in Russian heartland, including 90 killed in the simultaneous aircraft bombings over two Russian regions in 2004. Riyad-us Saliheen also took responsibility for the involvement in the hostage crises in Moscow in 2002 and Beslan in 2004, which together have resulted in more than 500 hostage fatalities. In 2005 the group had been reportedly disbanded by Basayev under pressure from the Chechen separatist president Sheikh Abdul Halim, as a condition for Basayev to enter the official leadership of the separatist government. In any case it did not display any activity for more than four years after September 2004.