FACTBOX - Major incidents of unrest in China since 1989

BEIJING (Reuters) - At least 140 people have been killed and hundreds arrested in rioting in the capital of China's northwestern region of Xinjiang.

The following are facts about some major incidents of unrest since 1989 when troops crushed student-led pro-democracy protests centred on Tiananmen Square in Beijing.

* 1989:

MARCH - Beijing said at least 16 people were killed and more than 100 injured during three days of pro-independence riots in Tibet's regional capital Lhasa. Exiled Tibetans said as many as 60 people died.

JUNE 4 - People's Liberation Army troops and tanks crushed the Tiananmen protests on June 3-4. The Beijing city government at the time put the death toll at more than 200 while insisting no one died on the square itself. But independent groups have estimated that hundreds, perhaps thousands, died.

* 1993:

SEPTEMBER - A cartoon about Muslims and pigs in a Chinese joke book sparked mass protests in the northwestern provinces of Gansu and Qinghai. Thousands of paramilitary police stormed a mosque taken over by armed Hui Muslims in Xining, provincial capital of Qinghai, and opened fire, wounding more than 10.

* 1997:

FEBRUARY 5 to 10 - About 1,000 people, mostly Uighur farmers and unemployed youths, rampaged through Yining near the border with Kazakhstan. China said nine people were killed and at least 198 wounded. Uighurs in exile said that the real death toll was between 80 and 90.