A thousand college students rioted in central China this week, scuffling with police and overturning cars after city inspectors beat a female student, a human rights group said Thursday.

Hundreds of police were called for backup as students from three universities surrounded the two inspectors who had assaulted the student and knocked out her front teeth Wednesday night, the Information Center for Human Rights and Democracy said in a statement.

The students overturned a police car and a car belonging to the city inspectors in Zhengzhou, the capital of Henan province, the statement said. One car was set on fire during the four-hour riot.

The Hong Kong-based rights group said police led away five students, but it was not clear if they were detained.

The local Dahe newspaper, citing information from the city government, said authorities met overnight to decide how to punish the inspectors. Six were detained, two were demoted and four received administrative discipline, the newspaper said.

It was not clear why the city inspectors assaulted the female student or whether her stall was illegal. The inspectors regulate street vendors, making sure they have proper licenses and are selling in permitted areas.

In the newspaper's account, residents and students came out to watch after inspectors confronted the student. In the process, conflict broke out between inspectors and some "individual" students and citizens, the newspaper said.

Officials with the city's police, public security bureau, communist party and hospitals all said they were "unclear" or "not aware" of the riot.

Campus unrest is treated with extreme sensitivity in China, where 1989 student pro-democracy protests led to the bloody military crackdown in Beijing's Tiananmen Square.