Q+A-Deadly ethnic riots in China's northwest

By Emma Graham-Harrison

BEIJING (Reuters) - At least 140 people have been killed in rioting in the capital of China's northwestern region of Xinjiang, with the government blaming exiled separatists for the Muslim area's worst case of ethnic unrest in years.

Hundreds of rioters have been arrested, the official Xinhua news agency reported, after Uighurs took to the streets of the regional capital on Sunday, some burning and smashing vehicles and throwing rocks at ranks of anti-riot police.

WHY ARE UIGHURS RIOTING?

The riots followed a protest about government handling of a June clash between Han Chinese and Uighur factory workers in southern China, where two Uighurs died.

But the underlying cause of the unrest was probably long-standing economic, cultural and religious grievances, which have built up over decades of tight central rule and periodically erupt into violence, though never before on such a deadly scale.

"In Xinjiang one of the major sources of discontent is that there is still a major gap economically between Han and Uighurs," said Barry Sautman, a specialist in China's ethnic politics at the Hong Kong University of Science and Technology.

"There are also people who object to the amount of control exercised by the state with regard to religion and there are people who resent that the Han population is substantial."

WILL THERE BE MORE RIOTS?