Five American church workers were detained by authorities in northern China in raids on underground Protestant groups.

A church meeting was broken up in Luoyang in Henan province Monday, resulting in the detention of four Americans, including a married couple, and 27 Chinese citizens, reported the Texas-based Christian-persecution monitor China Aid Association.

In the nearby city of Yichuan, police detained another American, according to a local pastor, Wan Dagan.

The Texas group said it did not have the names of the Americans.

The vast majority of Christians in China, perhaps as many as 100 million, are part of the unregistered church. The communist government requires all Protestant church activity to be under control of the official Three-Self Patriotic Movement, which restricts activities such as evangelism and certain teachings.

As WorldNetDaily reported, two Americans were roughed up by plain-clothes Chinese police during a raid of a house church earlier this month.

According to China Aid, the raid came during a crackdown on house churches that has seen 210 Chinese house pastors and members arrested since last month.

In March, China deported at least 10 foreign church leaders, including eight Americans, and detained 140 Chinese house-church leaders in connection with a training event in the country.

More than 100 security officers from five government agencies raided an office building where the Christians were meeting Feb. 24 in a suburb of Harbin, a major city in northeastern China,

Editor's note:For regular updates on the persecuted church, sign up for Voice of the Martyrs free monthly newsletter.

Related stories:

Americans roughed up in China

China arrests 100 young Christians

China arrests bishop

China deports U.S. church leaders

Chinese Christian testifies of torture

Top Chinese church leader arrested

100 church leaders arrested

Christian released under global pressure

Imprisoned pastor fears for life

Pastor beaten for leading inmates to Christ

Church leaders tried for revealing crackdown

Christians charged for revealing crackdown

Video shows China destroying church

Report: Police beat Christian to death

Protests help release Chinese Christian

Beijing bows to pressure on captured Christian