About a dozen police officers and urban management officers were injured in a riot in Guizhou province, with vehicles smashed and overturned. The incident was sparked by a clash between a driver and a group of urban management officers and the beating of a woman. Official media accounts of the incident in Qianxi county on Thursday were vague but they said at least 10 police and urban management vehicles were smashed and burned. Xinhua said calm had been restored by yesterday. The rioting, which involved thousands of people, has again put the spotlight on urban management officers. Used by the government across the mainland, they have a reputation for roughing up people from vulnerable groups, such as unlicensed vendors, and are known for overstepping their authority. Rumours about what happened in the incident spread quickly. A woman working in a grocery store on Yanshan Street in a downtown area of Qianxi told the South China Morning Post by phone that she did not see the reported scuffle, but heard that the urban management officers involved were drunk when they stopped a couple on an electric bicycle on suspicion that they were providing an unlicensed taxi service. She said the rioting was the result of anger over the officers' alleged beating of the woman. An official from the Qianxi government's publicity department said by phone that investigators sent by the provincial government were still trying to piece together what happened, but he denied that the five or six urban management officers involved were drunk. The official said angry mobs gathered at the county police department, county government compound and the building housing the traffic police, and some damage was caused, but none of the buildings were set on fire. The official denied that protesters used trucks to block roads leading to downtown areas, as reported by China National Radio. He said the vehicles had merely been stranded as a result of the rioting. He said that the riot ended at about 4am yesterday, and dozens of rioters had been taken away. He said they may be held on charges related to looting and ransacking. A man working in a downtown electronics store said that he arrived at the scene at about 6pm and saw at least one urban management vehicle overturned. He said the scene was chaotic and volatile, even after hundreds of police, including riot officers, were brought in. He watched from a distance and said he feared for his safety. 'But I was equally angry, and I knew it would happen,' he said. 'And I won't be surprised if it happens again if the urban management officers are allowed to mistreat people the way they did this time.'