Midland, Texas ? A prominent activist in China’s underground Protestant church has been released from a labor camp after serving a two-year sentence, a U.S.-based monitoring group reported Wednesday.

Zhang Yinan, 47, left a camp near the central China city of Zhengzhou on Sunday, according to the China Aid Assn., headquartered in Midland, Texas.

China’s officially atheistic Communist authorities allow worship only in tightly controlled state churches, and those who meet outside – often in members’ homes – are routinely harassed and fined, and sometimes sent to labor camps.

While underground church organizers can receive sentences of several years in prison, China Aid Assn. President Bob Fu said international attention given to Zhang’s case had persuaded China to give him a relatively light punishment.