BEIJING -- Christianity is on the rise in China, with the growing number of followers making Communist Party leaders nervous that the religion may soon undermine party dogma.

Officially, there are about 44 million Christians in the country. But according to Freedom House, a U.S. human rights group, this number is closer to 100 million if those belonging to "underground" or "house churches" are included. Of these, about 60 to 80 million are Protestant and 12 million Catholic.

And with the number of Christian converts increasing -- especially in economically distressed villages and cities where many feel alienated -- the party is trying to rein in the unsanctioned underground churches, fearing the spread of Western ideals, including those of human rights.

Last month, dozens of mostly middle- and old-aged women gathered at a Protestant church in a farming village in Huainan, a city in Anhui Province. The small church dates back about 100 years, when a U.S. clergyman arrived seeking to spread the faith.

The congregation numbers about 200 members, who typically start their days with morning prayers at 6:30 a.m. Many return later in the afternoon for confession or more prayers. Sermons are held three days a week, while on weekends parishioners gather to pray and sing hymns. Bible studies are also held at the church or at the homes of parishioners.

Christian villagers take their beliefs seriously. "Communist Party leaders and chief executives should learn the teachings of the Bible," said a local taxi driver, emphasizing the importance of Christian doctrine.

One villager in her 60s, who started attending the church five years ago after falling ill and given little chance of recovery, said, "So far I have been all right, thanks to my faith." Another elderly woman decided to become a member after her grown children moved away, leaving her feeling lost and lonely.

Christianity is the second most popular religion in China after Buddhism, which has between 185 and 250 million followers. The country is poised to overtake the U.S. as the world's largest Christian nation, according to one estimate.

U.S. Vice President Mike Pence noted in a recent speech that "faith in Jesus Christ has reached as many as 130 million Chinese Christians," eclipsing the roughly 90 million Communist Party members. Chinese Christians also far outnumber the country's 23 million Muslims.

Large Christian populations can be found in Hebei, Henan and Anhui provinces, mainly rural regions with large swathes of impoverished areas characterized by poor medical infrastructure. In fact, the less-than-adequate access to proper medical care could be one factor behind the regions' faith in Jesus.

But Christianity is not limited to the countryside. A Protestant church in Beijing's Haidian District attracts thousands of worshippers every weekend. The congregation has been growing steadily over the past decade. Many members are new converts, retired seniors or people without family or friends. Others have brought their faith from rural hometowns.

The trend is of growing concern to the atheist Communist Party, whose ideology is not to be challenged. China's constitution stipulates that people "enjoy freedom of religious belief" but with one major caveat: "No one may make use of religion to engage in activities that disrupt public order, impair the health of citizens or interfere with the educational system of the state."

At the Communist Party Congress in 2017, President Xi Jinping stressed that leadership should "persist in advancing the Sinicization of our country's religions," indicating his intent to tighten control over religion. He followed through in 2018 with more regulations, including stricter registration requirements for religious organizations and harsher punishments for unauthorized meetings.

A Catholic underground church overlooks the village of Huangtugang in Hebei Province in 2018. © Reuters

There have also been overtones of harassment. A large sign has been erected next to the Haidian church with a slogan marking the 70th anniversary of the country's founding. The sign admonishes citizens to "Follow the instructions and guidance of the Party." In addition, the church is surrounded by a fence and manned by a police officer, who checks the bags of people entering the premises.

The government is known to come down hard on even state-sanctioned churches if they fail to adhere to party "instructions and guidance," pulling down crosses and ordering congregations to praise the party. This has driven many Christians to the non-state-sanctioned underground churches.

At one of these, members congregate secretly to study parts of the Bible not discussed at official churches. The weekly gathering attracts government employees and members of the military who are unwilling to reveal their beliefs. An expert at a government think tank says the congregation has many corporate CEOs and employees, as well as highly educated people seeking greater religious freedom.

But the consequences of running or attending an underground church can be severe. Last December, police shut down Early Rain Covenant Church in the southwest city of Chengdu, arresting the pastor and 100 members of his flock.

Still, it seems the harder the Communist Party's cracks down, the more Christians turn to underground churches, even as Xi shows no letting up on his iron-fisted approach to curtailing religious freedoms.