Chinese authorities detained 28 Christians in a raid on a non-government-authorized church service at a private home, an overseas monitoring group said Friday.

Three members of the congregation, including the host and the presiding minister, were still being held following the May 28 action in Henan province, reported the Texas-based China Aid Association.

All others have been released, some after paying fines of 1,600 yuan (US$200;euro157), said the group. Host Chen Xuelan, 58, another woman, 55-year-old Cao Yan, and pastor Li Shunmin were being held at the Bayi prison in Henan's Fugou township, the association said.

Police produced no identification or legal documentation during the raid, and confiscated Bibles and notebooks belonging to the congregation without issuing required receipts, the report said.

It said members of the congregation planned to sue over the action and two lawyers have agreed to take up the case on behalf of a group calling itself the Chinese Christian Legal Aid Association. No other information about the group was immediately available.

Countrywatch:China

Bayi prison had no listed phone number and officers contacted at police headquarters in Fugou township and nearby Zhoukou city said they had no information about the reported raid. The officials refused to give their names because they weren't authorized to speak to reporters.

Chinese law does not allow Christians to worship outside the Communist Party-controlled Protestant church, although millions do so in underground congregations that have spread across large parts of China.

Those congregations, often called "house churches" because they gather in private homes to avoid detection, are subject to frequent raids and alleged harassment and extortion from police.