Protesters have camped outside an east China-based solar panel manufacturer accusing it of dumping toxic waste into a river, China's official Xinhua news agency reported on Sunday.
The protests began on Thursday in the city of Haining in Zhejiang province, when as many as 500 people stormed a compound owned by the New York-listed Jinko Solar Holding Co and overturned vehicles before being dispersed by police, Xinhua said.
Toxic waste from the factory, which manufactures photovoltaic panels, cells and wafers, killed large numbers of fish in a nearby river, and authorities had already ordered the company to suspend operations, the news agency said.
Protesters put up banners with the slogan "Return our lives to us, stay away from Jinko", according to photographs published on the website of the National Business Daily newspaper (www.nbd.com.cn) on Sunday.
Xinhua quoted an environmental official as saying that Jinko had failed to bring the problem under control and the factory's waste disposal facilities had been failing pollution tests since April.
Pollution has emerged as one of the biggest problems facing China's ruling Communist Party, which has struggled to contain growing public anger against industries improperly dumping toxic waste.
Thousands of protesters forced the closure of a deadly paraxylene plant after marching on the city square in northeastern China's Dalian in August.