Shouwang Church, which has about 1,000 members, has stated that it has no political motives in holding its outdoor services.

The church says it has no choice but to do so because it was evicted from the restaurant it was meeting in and the government has allegedly interfered and prevented the congregation from securing a permanent location.

“The church’s position remains unchanged. We will continue to gather outdoors until the Lord shows us the way,” said a statement from Shouwang’s governing committee, BBC reported on Tuesday.

But the church assured that its outdoor events are “purely religious activities”.

“They have nothing to do at all with politics or some people’s rights activities,” the church said.

On Sunday, authorities arrested more than 100 worshippers attending the open-air service, forcing them onto buses and taking them to an unknown location.

China Aid Association, a religious freedom group based in Midland, Texas, said everyone has been released except for a pastor and his wife, and one female believer who are still detained.

According to China Aid, surveillance vehicles remain outside the apartment buildings of many Shouwang members. "ChinaAid believes that their freedom of movement will remain restricted for some time to com," the organisation said.

The communist Chinese government keeps a close eye on organisations, groups, and individuals that have the potential to oppose its authority. Political dissidents and human rights lawyers, including Christians Liu Xianbin and Gao Zhisheng, have been given heavy jail sentences for criticising the government or challenging unfair policies in the court.

Unregistered churches, also known as house or underground churches, and their members have been particularly targeted by the Chinese government because they operate outside of government supervision.

Religious groups in China are required to register with the government and operate under official religious bodies. For Protestant churches, that means operating under the Three-Self Patriotic Movement and the China Christian Council (TSPM/CCC).

House churches refuse to register with the TSPM/CCC, arguing that doing so would mean putting the Chinese government as the head of the church rather than Jesus Christ.

Elder Fu Xianwei, chair of the Three-Self Patriotic Movement, says there are over 23 million Protestant Christians, including non-registered believers, in China. However, many reports have estimated that the unregistered Christian population could be as high as 100 million, surpassing that of the country’s Communist Party, which claims to have 78 million members.

Last week, Secretary of State Hillary Clinton criticised China’s negative human rights record.

"In China, we’ve seen negative trends that are appearing to worsen in the first part of 2011," said Clinton during the release of the US State Department’s annual human rights report.

Clinton particularly highlighted China for being guilty of cracking down on civil society activists, including lawyers, activists, and bloggers. She called on China to release those detained for exercising their “internationally recognised right to free expression”.