Chinese police detained some 300 people and urged others to give themselves up after the death of a teenage girl sparked rioting by up to 30,000 people, a human rights group and state media said on Monday.
The rioters believed that authorities in Weng'an county, in the south-western province of Guizhou, had covered up the rape and murder of the 15-year-old girl because the chief suspect was the son of a top county official, the Hong Kong-based Information Centre for Human Rights and Democracy said.
The number of arrests had risen to 300 by Monday and some 2,000 police were patrolling the county town following the rioting, which began on Saturday, the centre said in a statement.
The county television station broadcast a government demand for other rioters to surrender, while the injured uncle of the dead girl disappeared from a local hospital on Monday without discharging himself, it said.
A Weng'an county government official confirmed by telephone that rioters were asked to surrender but called the Information Centre's count of one dead, 150 injured and hundreds arrested "impossible."
The official said police who confronted the rioters did not carry guns and that several officers were injured.
"Now the government has made an announcement to ask people who took part in the riot to confess their crime before July 3, otherwise they will be punished harshly if found out by the government later," she told Deutsche Presse-Agentur dpa.
She said the girl's death was a "total accident."
The girl told her friend's boyfriend that she wanted to kill herself and then jumped into a river, the official said.
State media said the rioters damaged at least 20 vehicles and set fire to a police station and county government offices on Saturday.
Xiao Song, the deputy head of the county government, told the official Xinhua news agency that the crowd had reached up to 30,000 people at one point.
People with no knowledge of the circumstances surrounding the girl's death were "incited to mob the buildings", forcing the police to use tear-gas, the agency said.
A preliminary investigation found no connection between the death and any children of local officials and the girl's death, Xiao was quoted as saying.
The agency said 100 armed police were patrolling the area near the county government building on Monday.
It said the girl was a 17-year-old middle school student and that a preliminary police report said she drowned in a river.
The riot is the latest of an increasing number of protests and violent incidents in recent years, reflecting simmering unrest over abuse of official powers and widespread cynicism towards the ruling Communist Party in many poor areas, reported dpa.