KUALA LUMPUR — There was never the slightest doubt in the mind of a single reputable expert anywhere in the world that China was a caldron of ethnic unrest ready to boil over. Nor was there the slightest possibility that the masters of the People's Republic of China would be able to escape, within its capacious borders, some measure of the Muslim assertion of identity that was flaring up elsewhere.

In fact, when the previous American government sought out a helping hand from other countries in its infamous "war on terror" after the Sept. 11, 2001, attacks on the United States, Beijing, noticeably, did not say no. It had, after all, its own "Muslim problem" and could anticipate its own future pain — and thus the need for understanding by others, if it could get it, should a crackdown prove necessary. And indeed, China's turn has come.

Its problem, in the far western desert plains of China, concerns the Uighurs, the Turkic Muslim ethnic group that once dominated Xinjiang Province. But with the massive Chinese Han influx, aggressively promoted by the central government, Uighur identity had come under siege.