About 5,000 villagers clashed with police in eastern China after laying seige to a coal mine blamed for damaging local farmlands, a human rights group said Thursday.

The villagers had "surrounded and attacked" the coal mine in a rural county of Anhui province on Tuesday, the Hong Kong-based Information Centre for Human Rights and Democracy said in a press release.

Police in Fengtai county confirmed the protest took place but said only about 1,000 people were involved and denied there was any clash with police.

"They wanted the coal mine to stop operating in the villages because the lands have sunk due to the mining," a police officer who refused to give his name told AFP by phone.

"No conflict happened between police and the people."

However, the human rights group, quoting local authorities, said the crowds fought with police, smashed up a police car and injured the county's vice chief, Ma Shiping.

Residents say the Gubei coal mine has caused land subsidence that has affected 50,000 people in the area, with a total of 8,000 hectares (19,800 acres) suffering cave-ins, the rights group said.

It said more than 1,000 paramilitary police had been sent to the area to restore calm and that local officials were trying to resolve the dispute, but that 5,000 people were still at the mine on Thursday.

"Local leaders and the coal mine have been holding meetings to resolve the issues raised by villagers these days, but we need time," the police officer told AFP.

He denied villagers were still gathered at the scene.

China sees tens of thousands of protests or outbursts of violence every year, often stemming from land disputes or dissatisfaction with local authorities.

China's rulers are particularly concerned about unrest in 2009, which will see a string of sensitive anniversaries including 20 years since the Tiananmen massacre and 60 years since the founding of the communist republic.