A look at previous acts of violence in Xinjiang.

In January 2007, police destroyed a terrorist training camp in the Pamir plateau, killing 18 terrorists and capturing 17. They also seized 22 hand grenades, more than 15-hundred half-finished grenades, and home-made explosives. One officer was killed and another injured.

Chinese police smashed a terrorist gang on January 27, 2008 in Urumqi, the regional capital, killing two and arresting 15 others. Five police were injured when three homemade grenades were thrown at them.

On March 7, 2008, a 19-year-old ethnic Uygur woman attempted a terrorist attack on a China Southern Airlines flight from Urumqi to Beijing. The attempt was foiled.

Two terrorists, armed with guns, explosives, knives and axes, drove a heavy truck onto a team of more than 70 police in a regular morning exercise in Kashgar on August 4th last year. Seventeen people were killed and 15 injured in the attack four days before the Beijing Olympics.

On August 10, 2008, serial explosions occurred in the early hours in various supermarkets, hotels and government buildings in Kuqa County. A security guard was killed and two policemen injured. Police shot dead eight terrorists, and two other terrorists blew themselves up.

(CCTV July 8, 2009)