Six Christian leaders remain in detention in central China following coordinated police raids on several house churches, according to religious freedom charity ChinaAid.
The organisation said most of the Christians detained during the operation in Yueyang, Hunan Province, on 11 July have since been released, but six pastors and church workers are still being held.
Those still in custody are Pastor Huang Lei, Elder Yang Jianjun, Preacher Hu Hongtao, Pastor Luo Kaimin, Sister Yang Chun and Brother Fu.
ChinaAid said those released described being subjected to lengthy interrogations, fingerprinting, blood collection for DNA sampling, voice and video recordings and the creation of personal surveillance files.
One Christian woman reportedly refused to read a police prepared statement containing banking information because she feared it could be used for fraud. Officers eventually allowed her to identify herself using only her name and telephone number.
Another woman, who said she struggled to read because of poor eyesight, asked if she could pray instead before the recording. According to ChinaAid, police allowed her to end by praying a blessing.
Pastor Huang Lei's wife, Wang Ling, said officers confiscated every Bible and Christian book from their home during the search.
Teacher Yuan Siying is also said to be under pressure because her husband works for the government and their daughter is a university lecturer. Her husband was required to sign a written guarantee promising to keep his wife at home and stop her from attending church.
Dr Bob Fu, founder and president of ChinaAid, described the raids as part of a continuing campaign against unregistered churches.
"The July 11 crackdown in Yueyang demonstrates that under Xi Jinping, the Chinese Communist Party continues its systematic campaign to eradicate independent house churches," he said.
According to Christians released from custody, police repeatedly claimed that believers who refuse to attend the state sanctioned Three Self Church belong to a "cult". Those questioned rejected the accusation, arguing that Three Self churches restrict children's participation in church life, which they believe conflicts with Jesus' teaching.
ChinaAid said the reports of Bible confiscations, compulsory biometric data collection and pressure placed on family members to monitor one another, all point to increasing restrictions on religious freedom.
