In Henan province in central China, thousands of students attacked a county government office, smashing windows and clashing with riot police. Students from a local high school took to the streets to try and stop a developer from building apartments on their sports ground.
Tensions spilled over into violence after two girls were injured in the scuffles with police, and the students surrounded the government building at noon, the Information Centre for Human Rights and Democracy said.
Last week, large numbers of soldiers and armed riot police were sent to quell two major protests. In central Hunan province, 5,000 soldiers and armed police converged on a furious crowd of up to 10,000 demanding money back from an alleged fundraising fraud relating to real estate.
The disturbances took place in Jishou city, and 50 people were injured in rioting and police arrested 20 people, the Hong Kong-based rights group said.
Local government officials said they had launched an investigation into the Fuda Real Estate Company, which was behind the fundraising. Images of the unrest were widely available on popular web portals in China, causing quite a stir. Images showed rows of riot police carrying shields on railway lines and on the roads.
State media reported that executives of the company were "controlled", which presumably means arrested, and the petitioners dispersed after registering their investments with local authorities.
In the booming industrial region of Ningbo on the east coast, up to 10,000 people gathered around a factory after a young boy was injured, apparently after being thrown out of a factory window. The government insisted that the boy had jumped from a window after workers found him hiding in the factory, adding he was in hospital in a stable condition with a broken leg.
There were up to 20 injuries in the clashes, including one policeman, after officials arrived to clear the area. A yawning wealth gap in China leads to thousands of protests every year, but there have been some particularly intense clashes in recent months.
Often the causes of the riots are rumours of injustice which become exaggerated and turn into widescale rioting.
In June, thousands of residents rioted and torched police and government buildings in Guizhou province, after claims spread that police covered up the rape and murder of a girl.