China has detained a prominent minister of an unofficial Protestant church (search) in a crackdown on Christian groups that defy Communist Party (search) control, a U.S.-based group said Friday.

Pastor Zhang Rongliang was taken away Dec. 1 from an apartment in a village near the central city of Zhengzhou, the China Aid Association (search) said in an e-mailed news release.

The communist government allows worship only in state-supervised churches, which claim about 11 million members. Worshippers and clergy in unofficial churches are regularly harassed and detained.

The China Aid Association, based in Midland, Texas, said Zhang's two congregations — the Fangcheng Mother Church and China for Christ Church — are among China's largest underground church networks, with an estimated 10 million members.

Later on the day of Zhang's detention, police conducted house-to-house searches of the village, apparently looking for his wife and children, who were not home when he was detained, the China Aid Association said. It said they are now in hiding.

Police searched Zhang's apartment and confiscated digital video discs, publicity materials and photographs revealing contacts between Zhang's church and those overseas, the group said.

Contacts with foreign evangelical groups are considered especially sensitive because communist leaders regard them as possible channels for foreign subversion.

A man who provided Zhang with fake documents to avoid detection was also detained and at least three churches were raided in Fangcheng, a county in the central province of Henan where Zhang's followers are concentrated, the China Aid Association said.

A woman who answered the phone at the Zhengzhou headquarters of the State Security Bureau refused to answer questions or transfer the call to other departments. Calls to the State Security Bureau in Fangcheng were answered by an answering machine.

A man who answered the phone at the Religious Affairs Bureaus in Zhengzhou said he had never heard of Zhang and couldn't comment on groups deemed illegal by the authorities.

The Fangcheng church was designated a cult in 1999 amid a major clampdown on independent religious groups. According to the China Aid Association, Zhang was sentenced to two years in a labor camp, though it wasn't clear whether he served the full term.