A religious rights organization says China has detained a Roman Catholic priest for holding illegal services. Rights activists say China already has many priests and bishops from the banned church in custody or house arrest.

The U.S.-based Cardinal Kung Foundation says officials detained 37-year-old Reverend Dong Yingmu as he was on his way to celebrate Christmas Mass in December. Reverend Dong's imprisonment has just come to light.

Foundation head Joseph Kung says Reverend Dong was arrested in the city of Baoding in Hebei Province, where police have detained several priests and two bishops in recent years.

China's communist government allows about four million people to participate in the officially approved Patriotic Catholic church. The officially atheist Communist Party tolerates only religious groups it has approved.

Unlike the official church, the unapproved, underground Roman Catholic church recognizes the pope in Rome as its spiritual leader. The unapproved church claims millions more members than the Patriotic Catholic organization.

A researcher who is an expert on Chinese society, Jean Pierre Cabestan, says Beijing strictly controls religious groups because the Communist Party does not want competition. "These religious groups become so powerful that ... the power of the Communist Party and its organizing strength will weaken," he said.

Mr. Cabestan, who heads the French Center for the Study of Contemporary China, based in Hong Kong, says religion is becoming more important in Chinese society. "Partly because of the void created by the collapse of the communist ideology and the lack of a spiritual ideal within the society and the worship of money and growing cynicism in Chinese society today," he explained. "So people tend to take refuge in religion.

Professor Cabestan says China's government is following two contradictory policies, showing more tolerance for religious practices in general, but cracking down harshly on religious groups perceived to be powerful or foreign.

He says the unapproved Catholic Church's links to Rome worry Chinese officials.

A government religious affairs official says the detention of Reverend Dong "never happened." The government insists that it allows freedom of religion and denies that it mistreats anyone on the basis of faith.