Police listed Li Shifei's death as suicide. The her uncle, a teacher was reportedly beaten to death when he questioned the police. -- PHOTOS: AFP

View more photos

As many as 10,000 people were involved in the protest in Weng'an county of Guizhou province.

Seen in pictures posted online, rioters smashed the windows and wrecked the facade of at least one government building. They also overturned and torched several police cars. Plumes of black smoke and fire could be seen rising from the burning vehicles.

The unrest happened amid heightened security concerns just 39 days before the start of the Beijing Olympics. President Hu Jintao has stressed that ensuring stability is a top government priority ahead of and during the Games.

The Guizhou protest also follows several incidents in recent months, including the March riots in Tibet and smaller protests by parents whose children had died in schools that collapsed during the May 12 Sichuan earthquake.

Unverified accounts of the Guizhou riot, including a report by Hong Kong's Ming Pao, identified the girl as 15-year-old student Li Shufei.

She was said to have been raped and murdered by the son of a high-ranking Weng'an county official and another youth. Her body was then dumped into a river.

The alleged assailants were detained by local police but released on the same day without being charged. Police later said the girl had committed suicide.

Outraged by the official explanation, her relatives sought out the police but were reportedly assaulted instead. Her uncle, a local teacher died after a severe beating, according to the reports.

His death was said to have prompted his students to march on the local authorities, triggering a bigger protest.

The Hong Kong-based Information Centre for Human Rights and Democracy said up to 150 people were injured in the clashes with the police.

Some 200 rioters have been arrested. More are likely to be detained as police round up people identified in footage of the riots. Over 1,500 paramilitary and riot police have been dispatched to the county, the centre said.

Photographs as well as comments on the Guizhou protest in chatrooms and forums were quickly deleted by China's Internet censors, but not before some of the content was captured by websites hosted overseas.

In a rare move, the official Xinhua news agency reported the Weng'an incident yesterday, but said only that riots had started because people were 'dissatisfied over the medical and legal expertise over the teenager's death'.

'When officials were handling the case, some people who didn't know about the exact context of what had happened were instigated to mob the police station and the office buildings of the county government and Communist Party committee,' Xinhua added.

The number of protests and riots across China have increased in recent years over many issues including corruption and unlawful appropriation of farm land.

The unrest is proving a tough challenge to Mr Hu's attempt to build a 'harmonious society'.

These incidents often go unreported by Chinese media. Accounts, however, increasingly appear online as more Chinese turn to the Internet to give their version of things.

The Public Security Bureau has stopped making public the annual number of mass incidents - a term Chinese officials use to refer to large-scale unrest. The latest figures show there were 87,000 mass incidents in 2005, up 6.6 per cent on 2004 and 50 per cent on 2003.

tracyq@sph.com.sg

ADDITIONAL REPORTS FROM REUTERS AND AGENCE FRANCE-PRESSE