There have been clashes between police and Christians protesting against the demolition of a church in eastern China's Zhejiang province, reports say.
People are allowed to worship in state-sanctioned organisations
The violence occurred when up to 500 police tried to break up a 3,000-strong protest, a rights group said.
Twenty people were hurt, including four who were seriously injured, the Hong Kong-based Information Centre for Human Rights and Democracy said.
A police official confirmed an incident had taken place on Saturday.
He told the French news agency AFP that the church in the suburb of Xiaoshan had had to be destroyed.
"It is clear that this church was an illegal structure, it did not have the approval of the religious affairs bureau or the government," he said.
A local state newspaper, the Hangzhou Daily, reported the demolition of an "illegal building".
"A tiny handful of people with ulterior motives incited members of the public who did not know the facts," the paper said.
China has enacted new laws which in theory guarantee its citizens religious freedom.
But in reality religious activities are strictly curtailed, with worshippers limited to state-sanctioned organisations.
According to human rights advocates, many religious groups continue to be harshly repressed - from the banned Falun Gong spiritual movement to underground Catholic and Protestant churches.
Xiaoshan, a suburb of the provincial capital Hangzhou, has a sizeable community of Protestants.
The rights group said the provincial authorities had issued orders in June to crack down on "illegal religious buildings".
But one resident suggested the move was less about religious freedom than money.
"They wanted to build a church, but the government said the land is too valuable for that," the woman told Reuters news agency.