Police clashed with protesters demanding the closure of a battery factory in eastern China they accuse of spewing lead into the environment, and dozens of people were injured, witnesses and hospital officials said Sunday.

After the initial melee, thousands of demonstrators torched police cars and broke into government offices in the town of Meishan in Zhejiang province, witnesses reported.

Such scenes of frustration are becoming more common in rural China as villagers vent their anger against corruption, environmental degradation, pollution and the seizure of land for real estate development.

Last month, villagers using rocks and farm tools attacked a pharmaceutical plant in Xinchang, also located in Zhejiang province, forcing it to suspend production. Runoff from the plant was polluting irrigation water, the protesters said, stunting the growth of local crops.

The violence in Meishan began Saturday after a large crowd gathered outside the Tian Neng Battery Factory, to demonstrate against lead pollution, said a villager, who declined to give his name because he feared retribution.

"Police fired tear gas into the crowd and beat innocent bystanders," the man said in a telephone interview. "I also saw some ambulances go through the area to pick up injured people."

Another man, who also spoke on condition of anonymity, said about 1,000 police officers later went to villages and harassed and beat those who had participated in the protest, injuring at least 10 of them. The police were holding shields and wearing helmets, he said.

The man said as many as 5,000 residents retaliated later that night by "breaking into government offices and burning police cars." He said the protesters wanted the factory to shut down or move, but company officials refused.

Telephone calls placed to the factory and Meishan police and government offices were not answered Sunday. A man who answered the phone at the Changxing County government office, which oversees Meishan, said he had "never heard of the case."

At the emergency ward of the Changxing County Hospital, a woman said between 60 and 70 people were treated Saturday for minor injuries related to the incident. She said most had been discharged, but she refused to provide any other details or give her name.