Ethnic tensions in the far western autonomous region of Xinjiang have again flared into violence. In the worst single incident since rioting between Muslim Uygurs and Han Chinese six years ago left 197 people dead, last week 15 community workers and police were among 21 killed in a clash involving knives, axes and the burning down of a house. Authorities quickly branded it a terrorist attack and there have been calls for the crushing of jihadist cells. But rushing to conclusions and responding with brute force are not helpful where so sensitive a matter is concerned. While immediate threats have to be dealt with, a transparent investigation and report are also necessary. What took place last Tuesday in the Kashgar town of Selibuya is disputed. Authorities say the clash erupted during a search of homes after a tip-off of suspicious activity, but ethnic groups claim it began when a young Uygur man was killed by Han Chinese police. Independently determining what took place is difficult given the challenges outsiders have in obtaining information. Journalists face intimidation and harassment when trying to verify reports of ethnic unrest. The "three evil forces" - terrorism, extremism and separatism - is a term oft-used by officials where unrest involving Muslim-majority Uygurs is concerned. State-run media pointed out after the latest attack that the "battle was still severe and challenging". But Uygur groups tell another story, accusing authorities of exaggerating circumstances to justify crackdowns. They say their culture, religion and traditions are threatened by development and an influx of migrants. Tensions are especially rife in Kashgar, which has undergone rapid development in the past decade. Where it was once almost entirely Uygur, it is now one-third Han Chinese. Uygurs complain that they are missing out on the economic growth and their way of life is disappearing. But Xinjiang has vast mineral, agricultural and water resources and is the main route for trade with central Asia, making it one of the nation's most important regions; change is inevitable. Nonetheless, development also has to take into consideration the region's ethnic attributes. Ethnic conflicts are among the most intractable of political problems. Uygur identity has to be respected and cultural and economic security ensured. Terrorism and extremism cannot be tolerated, but such terms should not be carelessly thrown about. They are justified only after full and open investigation.