China has witnessed an increase in the number of “illegal” Christian groups who have been arrested across the country after a crackdown ordered by the Chinese government last month, reported a Chinese persecution watch group on Friday.

Since mid-July, a string of arrests and other forms of persecution in at least eight Chinese provinces has taken place including Inner Mongolia, Xinjiang, Jiangsu, Henan, Shandong, Shanxi and Anhui, according to China Aid Association (CAA). At least 17 Christian leaders of unregistered churches have been detained.

Chinese Christians are only allowed to worship in Communist-controlled churches. All activities outside of designated churches are deemed illegal and members of the underground church face fines, imprisonment, and sometimes even torture.

Authorities have imprisoned some while others are punished for hosting Sunday schools in their homes by having their water and electricity cut off by the government.

“The Chinese church believers are faithful peace-makers in building a stable moral society in China,” stated the Rev. Bob Fu, president of CAA.

“We call upon the Chinese government to correct this grave misunderstanding by allowing these faithful to contribute more social services without fear of arrest and retribution,” he urged.

Among the arrested are seven church leaders, including four pastors, from Inner Mongolia during a house church meeting. In the Jiangsu province’s Jianhu city, three other church leaders were wounded and detained after a house church raid during a Sunday worship service. The same church was attacked on July 11 during its summer Vacation Bible School for 150 children.

Meanwhile, prominent Christian businessman Zhou Heng has been under criminal detention since Aug. 3. He was arrested when he tried to pick up two tons of Bibles at a bus station sent by someone from another province to distribute to local believers. His detention paper read that he was put on criminal detention for “suspicion of illegal business operation,” according to CAA.

Zhou could be imprisoned up to 15 years if convicted as the Chinese government only allows officially sanctioned churches to print and distribute limited numbers of Bibles.

The crackdown order by authorities is part of a national campaign against crime and economic disorder in the villages, according to The Associated Press.

“Strike hard against illegal religious and evil cult activity; eliminate elements that affect the stability of village governance,” read a directive posted at the official website of the Ministry of Public Security on July 6, according to AP.

China has increasingly clamped down on Chinese house church Christians and even foreign missionaries as the next year’s Olympic Games in Beijing nears. Between April and June more than 100 foreign missionaries were expelled from China as part of a government-sponsor campaign to prevent evangelization during the Olympics. The government has also reportedly escalated its campaign against unregistered church activities to prevent protests or other disturbances at the 2008 Olympics.

However, the persecution has instead gained international media attention with many human rights and Christian groups calling for people worldwide to boycott the Games if China does not change its ways and show greater respect for human rights, including religious freedom.