Hundreds of protesters overturned police vehicles and threw bricks after a migrant worker was beaten up for refusing to pay for a resident's permit, a newspaper said. It said several people were hospitalized with injuries.

The riot on Monday night in Guiyang, the capital of southern Guizhou province, highlights tensions over China's tens of millions of migrant workers who have left the countryside to look for work in cities, often settling in urban areas in violation of strict household registration rules.

Witnesses said the migrant, identified only by his surname, Guo, was stopped in a park by people hired by police to check identity papers, according to the state-run Guizhou Metropolitan News. Such civilian forces who assist police are common in Chinese cities.

Guo didn't have a permit to live in the city and refused to pay for one, the report said Wednesday. It said he was found shortly afterward bleeding from a severe head wound.

Police officers rushed to the scene and asked that Guo be sent to the hospital before going to a police station for questioning with the civilian security workers, the paper said.

"Hundreds of people clogged the surrounding area" and overturned police cars and motorcycles, as well as several taxis, the newspaper said.

Guiyang police refused to confirm the report on Thursday, saying the details had not been given official approval.

China has faced a growing number of violent protests over corruption and official abuses.

Photos on the Web site of the Guizhou Metropolitan News showed a crowd surrounding a white police van lying on its side and a man, identified as Guo, lying on a hospital gurney, his head bandaged and blood streaming down his face.

One taxi driver was beaten "until he bled from his nose and mouth," the paper said. Other people who were injured were also taken to the hospital, it said without giving details.

The Guizhou newspaper said the mob also attacked reporters trying to cover the riot.