Hundreds of people protested against a proposed chemical plant in southwest China on Saturday, state-run Xinhua news agency reported, while local residents accused authorities of preventing a similar protest in another city.

Hundreds of people protested against a proposed chemical plant in southwest China on Saturday, state-run Xinhua news agency reported, while local residents accused authorities of preventing a similar protest in another city.

More than 200 protesters gathered in the city of Kunming to protest plans for a factory which will produce paraxylene (PX), a toxic petrochemical used to make fabrics, Xinhua added.

Police also lined the streets of Chengdu, the capital of southwest China's Sichuan province, after locals planned a protest against a nearby chemical plant Saturday.

Photos posted online showed ranks of police lining the city's streets. Local police on Saturday morning announced that they would be carrying out an earthquake protection drill, a claim dismissed by thousands of Internet users.

"Its about preventing the protest," one user of the popular social networking website Sina Weibo wrote in response to the police notice. "This is the most blatant in the history of Chengdu," added another.

Locals online said that the protest did not take place.

China has seen a number of urban demonstrations against proposed chemical plants in recent years, in what analysts have identified as a rising trend of environmentally-motivated "not in my backyard" protests in China.