Chinese security troops have killed two Uyghurs in Urumchi on Monday July 13. The reports, which have relied heavily upon official communist Chinese information, quote an Urumchi regime official who claimed that:

“The police fired into the air for warning, but it’s not effective. Therefore, the police shot them, according to law,”

According to information in a New York Times article 
http://www.nytimes.com/2009/07/14/world/asia/14xinjiang.html?_r=1
   a foreign witness to the events claimed that said she had observed police officers shooting into a four-story building in the mid-afternoon, and witnessed an “explosion in the middle of the street with smoke.”