The latest example of that persecution came Sunday as followers of an unapproved church in Beijing were again forced by the government to find a new place to worship.
Worship in China, governed by the officially atheist Communist Party, is allowed only in state-approved churches, but millions of people belong to unregistered churches that often face official harassment.
Sunday's banishment was the latest for the Shouwang church, one of the largest underground churches in China with about 800 members. It was forced to hold services in a park earlier this month after being kicked out of a rented indoor area. Photos and a video posted on the church's Web site, which was later blocked, showed hundreds of members gathered, holding snow-flecked umbrellas and Bibles.
On Sunday, police blocked church members again from meeting at the park, and hundreds ended up at a performance hall elsewhere in the city.
District police referred questions to the Beijing public security bureau, where calls rang unanswered Sunday. Calls to the State Religious Affairs Bureau also went unanswered.
Another well-known underground church in Shanghai, Wanbang, also has been told to close.
Harassing the two prominent unregistered churches is likely to intimidate other smaller churches. Members of the Beijing church said Sunday they have never experienced such harassment from authorities before.
Obama, who was to arrive in Shanghai later Sunday, will be closely watched during his visit for signs he will speak out on human rights, including religious freedom. Leaders of churches like Shouwang said if Obama doesn't speak up, the Chinese government will crack down even more.
"Sometimes before a major U.S. visit, Chinese authorities show goodwill and release someone. But this time, it's the opposite," said Yang Fenggang, director of the Center on Religion and Chinese Society at Purdue University. "I tend to think this is a test case."
Activists and others in China say the U.S. may not want to risk angering China when it needs cooperation on issues such as climate change and the financial crisis.
"I think so far President Obama has been the worst president in terms of dealing with China's human rights issue," said Fan Yafeng, an outspoken leader of another unregistered, or "house," church in Beijing.
He said the Chinese Academy of Social Sciences fired him Nov. 3 as a research fellow at its Institute of Legal Studies for political reasons, including his church activities.
"Human rights lawyers and house churches are two of the most important powers in China's civil society, but the president hasn't made any gesture to help them," Fan said.
Obama touched briefly on human rights and China in a major Asia policy speech in Japan on Saturday, but he did not mention specific issues.
The Obama administration's stance has worried many since February, when Secretary of State Hillary Rodham Clinton said the U.S. would not let human rights concerns interfere with cooperation with Beijing on global crises.
"The Obama administration's total silence on this issue was seen as a green light and certainly emboldens the Chinese government's resolve to carry out this sweep without worrying about international consequences," Bob Fu, founder of the U.S.-based Christian group China Aid Association, said in an e-mail Saturday.