Assailants using homemade bombs launched a series of attacks and battled with police Sunday in a western Chinese city far from the Beijing Olympics. Ten attackers and one security guard died, police said. The violence in the restive Muslim region of Xinjiang came despite tightened security for the games and followed threats by an Al-Qaeda-linked militant group that it would disrupt the sporting event. Police said that “violent terrorists” attacked a shopping center, hotel and government buildings in the city of Kuqa in west central Xinjiang. It said officers killed eight attackers and two others blew themselves up, while two were arrested. Three attackers were at large, it said. Xinhua News agency said the bombs were made from bent pipes, gas canisters and liquid gas tanks. The already-tight security in Xinjiang was increased after assailants killed 16 border police and wounded 16 others in Kashgar city on Aug. 4, ramming a stolen truck into the group before tossing homemade bombs and stabbing them. Wang Wei, vice president of the Beijing Olympic Organizing Committee, called the attacks the work of “East Turkestan terrorists.” “The very purpose of these attacks is all about separating the region from China,” Wang told reporters. On Thursday, a video purportedly made by the Turkestan Islamic Party was released in which the militant group threatened to attack buses, trains and planes during the two-week Olympic competition. Security experts say the group's core members have received training from Al-Qaeda. In Beijing, police released new details of the Chinese man behind the seemingly random attack on Saturday in which Todd Bachman, father-in-law of the U.S. men's volleyball team coach, was killed and his wife was wounded. The man committed suicide afterwards. The attacker -- a homeless, jobless, twice-divorced man – had no previous criminal record and “acted out of despair over personal failures”, Xinhua quoted police as saying.