Hundreds of Chinese students clashed with police after street inspectors reportedly beat up a female student.
Students from several universities in Zhengzhou, in the central province of Henan, rioted after a student vendor was beaten by several inspectors as they cleared her unlicensed stall, a student witness said.
"I was also selling things on the street, and I could not take it any more, when I saw them even beating up a girl, so I joined the riot by throwing a brick at the inspectors," a student from the Henan University of Finance and Economics said.
"I saw more than 10 people running after an inspector and trying to beat him, and some other people overturned a car and set fire to it," another witness said.
About 100 police, some armed with electric rods and shields, arrived on the scene, sealing the street and taking people away, the student said.
The Information Centre for Human Rights and Democracy put the number of students rioting at 1,000. One witness put it at 2,000.
Clashes are common between members of the public and the inspectors, who are mainly responsible for cracking down on unlicensed hawkers suspected of selling unsanitary food or low-quality goods.
Last June, thousands of students from the same city smashed windows and ransacked their campus in a riot sparked by anger over the wording of their diplomas.