The more Chinese authorities try to stamp out protests by repressed ethnic minorities, the fiercer those protests grow. Beijing should have learned that lesson after last year’s bloody anti-Chinese riots in the Tibetan capital of Lhasa. It didn’t. This week, clashes in Xinjiang between Muslim Uighurs and Han Chinese have left at least 156 dead and more than 1,000 wounded.

This round of trouble began on Sunday when Uighurs took to the street to demand a government inquiry into an earlier brawl between Uighurs, the region’s largest ethnic group, and the Han, the country’s dominant group. We don’t know who is responsible for that protest turning violent. On Tuesday, Han Chinese clutching meat cleavers, pipes and clubs spilled down side streets of the Xinjiang capital looking for Uighurs to target.

The Uighurs have long been mistreated. Beijing has invested heavily over the last decade to exploit the region’s rich oil and gas deposits and at the same time financed a huge influx of Han migrants.

Amnesty International said recently that the Uighurs’ identity and well-being are being “systematically eroded” by government policies that limit the use of the Uighur language, restrict religious practices and foster job discrimination. It accused Beijing of arresting thousands of Uighurs on bogus terrorism charges.