Massive riot in northwestern China

At one point, rioters met a surging wall of armed police officers with a hail of rocks, bricks, bottles and flowerpots. The crowd later confronted police with iron bars, axes and hoes as they tried to hijack a fire truck and smashed windows and office equipment in two government buildings.

The violence, one of the most marked instances of social unrest to grip China in recent months, was sparked by government plans to relocate the city of Longnan's administrative center after May's devastating earthquake, according to the Xinhua news agency.

State-run press has reported on numerous pickets and demonstrations that have broken out across China in recent weeks, including a two-day strike by disgruntled taxi drivers in the southwestern Chinese city of Chongqing.

Earlier this month, a crowd of 400 in the southern boomtown of Zhenzhen threw stones and set fire to a police car after officers tried to stop a motorcyclist at a checkpoint. The cyclist fled and was killed when he hit a lamppost.

In June, 30,000 people demonstrated in the southwestern province of Guizhou, setting fire to cars and the local Communist Party building following rumors that officials had tried to cover up the death of a teenage girl.

Activists warn that tensions over the sudden downturn in the Chinese economy could provoke similar public outbursts, even though police have made efforts not to immediately resort to violence in quelling the riots.

"The government's emphasis on maintaining a harmonious society just extenuates the levels to which it is worried about these kinds of threats to social stability," said Joshua Rosenzweig, a Hong Kong manager of research at the Dui Hua Foundation, a human rights group.

"I don't think we're even close to seeing the real impact of the global financial crisis on Chinese society. I'd be surprised if the government wasn't very concerned about the increasing level of social unrest all over China."

Chinese economists say that rising wages throughout China have led many laborers to expect better working conditions and residents to demand more accountable government. "The local government has become the front line of conflict," said Hu Xingdou, an economics professor at the Beijing Institute of Technology.