Thousands of people in east China's Shandong province rioted last week, storming a government building and smashing and looting equipment after an official vehicle ran over and killed a vendor, residents and a rights group said yesterday.

The riot - one of the largest in China in recent years - occurred on October 28, a day after a confrontation between officials and a man selling fresh pancakes from a roving stove-wagon in Zoucheng city.

The vendor, surnamed Shao, was selling the popular egg and onion dish on October 27 when some employees from the "city management" department confiscated his wagon, sources said.

Shao - seeing his source of livelihood being carted away - blocked the vehicle's path.

He was run over as a crowd watched, residents and the Hong Kong-based Information Center for Human Rights and Democracy said.

The next day, several thousand people stormed the city's communist party and government's offices in the same building, breaking through a police line of some 800 officers, residents and the Center said.

"The rioters were not necessarily people angry over the vendor's death. They were laidoff workers and other street vendors who were being ordered to stop selling merchandise on the streets," said a local resident surnamed Cheng.

"When they rushed into the building, some of the city workers had already gone home. The others were hiding and too scared to come out," Cheng said.

Rioters broke down doors to 20 rooms and proceeded to smash and loot furniture and equipment, the Center and residents said.

"They took computers, thermos flasks, even slippers," she said.

Center director Frank Lu said a police officer told him the city's entire 800-strong police force was mobilized but could not stop the rioters.

City police called for backup from three nearby cities, residents and Lu said, and eventually arrested up to 200 protestors.

"They later released about 100 people, but approximately 20 are still in custody," said one resident.

Officials Monday told AFP a riot had occurred, but played it down.

"On October 28, several dozen people went to the city government to appeal, including the family of the vendor. ... They smashed windows. These people stormed into the city government," said a city government office employee.

"They have ulterior motives. The police came and arrested some people. This has been resolved," he insisted.

Police declined to say how many people had been arrested.

Lu accused the city of trying to cover up the extent of the incident.

"Several police officers confirmed to me that several thousand people protested. A few days later, they said several hundred. Now they're telling reporters several dozen," said Lu.

A police officer at the Zoucheng city police station told AFP: "The city party committee ordered us not to speak about this."

Authorities in the city called in backup forces and the city was being guarded by large numbers of People's Armed Police. Streets were cordoned off a day after the riot.

Six employees of the "city management" office have since been detained, said Lu said, who added that the vendor's death ignited a strong reaction from residents because they were already angry with officials over unreasonable and harsh tactics.

Social instability appears to be growing in China with public dissatisfaction over a variety of problems and resentment against the government.