Hundreds of people overturned vehicles and attacked police in a city in southwestern China after security forces reportedly beat a street vendor to death.

Official Chinese media say the riots occurred late Tuesday in Anshun, a city in Guizhou province. The Xinhua news agency said Wednesday that about 30 demonstrators and 10 policemen were injured in the violence.

Local officials confirmed they are investigating the death of a street vendor that apparently sparked the riot. Online reports from the city say the one-legged hawker was fatally beaten after getting into an argument with members of the widely despised “chengguan,” an auxiliary force charged with monitoring street vendors and beggars.

Hong Kong-based Cable TV showed pictures of overturned cars, people throwing stones at police and bleeding protesters. It said water cannons and tear gas were used to disperse the crowd.

The riot is the latest in a series of disturbances across China that have called attention to simmering discontent over inflation, corruption and other social ills.

Earlier this month, six people were given jail terms for their parts in a three-day riot in southern Guangdong province in June. Hundreds of migrant factory workers took part in the riot, which was sparked by complaints that security forces had mistreated a street vendor and his pregnant wife.