Here's the Times Online (UK) with the latest on events in Uyghurstan. Hu Jintao is headed home from the G-8 to deal with the situation.
When things started, it was the Uyghurs on the march in response to incidents in Guangdong where first some Uyghurs were accused (falsely, it appears) of rape and tensions arose in a factory, leading to the death of some Uyghurs. Last night/today it was the Han who were on the march, demanding vengeance as they took the brunt of the violence when things started to get hot in Urumqi.
Still, in a larger sense, the Han have been on the march for some time, and that's the problem. We're dealing with an area called the Xinjiang Uyghur Autonomous Region, but of late Uyghur autonomy has been shrinking as Han Chinese move in. This is nothing against the Han Chinese who are moving there per se. But if the government is going to use the region as a place to offload Chinese that they don't know what to do with as the population grows, this sort of thing is going to happen. Today, Han Chinese demonstrated in the street to demand that their government keep them secure in their city. From their vantage point, this is reasonable. From the Uyghur vantage point, though, anything the Chinese government does to make sure Han Chinese have a stable place in Urumqi while doing little to protect Uyghurs, Tibetans and others in their own homelands, never mind outside of them, drives home the point that the Uyghur Autonomous Region is no longer Uyghur nor autonomous. The Chinese government has failed all its people - both its own Han population and the minorities whose lands they have colonized. For using ordinary citizens seeking only a new and better place to live as an invasion force to destroy a culture, they're now paying the price.
[Note: Post updated to correct for missed details from earlier.]