A Chinese city has announced it has scrapped plans for a copper plant after thousands of people protested the project's possible public health risks.

Shifang city in the southwestern province of Sichuan issued a statement on the Internet saying it had decided to stop the project.

The city's public security bureau earlier warned the public not to use the Internet or cellphones to organize more protests and asked those who had done so to turn themselves in within three days or face severe punishment.

Protests turned bloody

Thousands of people — including high school students — concerned about pollution the plant would cause began to gather in front of the city government building and a public square Sunday night, and the protests turned bloody Monday afternoon after riot police moved in.

Public anger surged as Internet users circulated photos and videos of riot police using tear gas and batons to end the protests. Some Internet users said one protester had died.

"People are very upset. How could the police beat them?" said a 15-year-old middle school student surnamed Liu who did not join the protest.

A man who answered the phone at Shifang No. 2 Hospital said more than 30 people — including police officers and protesters — were injured but that they were discharged after minor treatment. The man, who declined to give his name, said no one had died. City officials also have denied that anyone was killed.

In a public notice issued Wednesday, the municipal government said a small group of protesters threw pots, bricks and stones at police officers and government officials. It said 27 people were taken away by police, six of whom were formally detained for overturning police vehicles or throwing objects. The other 21 were released.

The city government had earlier said it would delay the project after the protest and educate residents about the plan.

Economic need

Shifang was badly hit in the 2008 Wenchuan earthquake that killed nearly 70,000 and left more than 18,000 missing. City officials say the copper plant project is needed to help Shifang rebuild its economy.

Liu said parents, classmates and teachers all objected to the project because of its environmental risks

"It will make our home city a town of death," Liu said.

Residents outspoken

Pollution problems are a leading cause of unrest as China undergoes rapid economic development, and citizens have become more outspoken against environmentally risky projects in their backyards.

Protests often bring at least a temporary halt to such projects, particularly when they involve the urban middle class. But local officials who are under pressure to deliver economic growth often restart them once the outrage dies down.

Last year, authorities swiftly closed and moved an urban chemical factory from Dalian in northeastern China when 12,000 people protested.