I would be a bit wary of the official Chinese line on this, it makes them look good when there were rising security concerns abotu the upcoming Olympics. Another reason that I am skeptical is that the Uighurs, a Turkic Muslim minority, have been a favorite target of the Beijing government for some time. Granted, some have shown up in Afghanistan on the wrong side of the conflict and there have been some attacks in western China attributed to them, but China has a nasty tendancy not being able distingush between legitimate/peaceful protest and terrorism (re: Tiananmen Square).