WASHINGTON — As Secretary of State Hillary Clinton flew to China on Tuesday, President Barack Obama was tight-lipped about the whereabouts of escaped Chinese activist Chen Guangcheng and his potential impact on the discussions to be held this week in Beijing.

“Obviously, I’m aware of the press reports on the situation in China, but I’m not going to make a statement on the issue,” Obama said in response to a question about whether Chen was under U.S. protection and whether the United States would grant him asylum if he were to ask for it.

“What I would like to emphasize is that every time we meet with China, the issue of human rights comes up,” he said during a joint news conference with Japanese Prime Minister Yoshihiko Noda at the White House.

“It is our belief that not only is that the right thing to do, because it comports with our principles and our belief in freedom and human rights, but also because we actually think China will be strong as it opens up and liberalizes its own system.”

“I have nothing for you on that subject,” State Department spokeswoman Victoria Nuland said in response to a question about whether Chen is in the U.S. Embassy in Beijing, as reports have said.

Nuland confirmed that Assistant Secretary of State Kurt Campbell was in Beijing, paving the way for Clinton’s arrival, but would not elaborate.

“I don’t have anything further on that,” Nuland said of whether Campbell’s visit was related to Chen.

When pressed, she continued, “I have nothing for you on anything having to do with that matter.”

Chen, a blind, self-taught lawyer, evaded guards who had kept him under house arrest for more than 18 months in a small eastern village and made his way to Beijing on April 22, friends and fellow activists said last week.

Once in the capital, Chen moved from safe house to safe house before finding refuge at the U.S. Embassy, according to Hu Jia, a fellow activist and one of the few people who have said he has seen Chen since he arrived in Beijing.

“This is a pivotal moment for U.S. human rights diplomacy,” said Bob Fu, president of ChinaAid, a Texas-based Christian human rights organization. He was quoted in a ChinaAid statement Sunday.

“Because of Chen’s wide popularity, the Obama Administration must stand firmly with him or risk losing credibility as a defender of freedom and the rule of law. If there is a reason why Chinese dissidents revere the U.S., it is for a moment like this.”

Appearing on CNN’s “John King, USA” on Monday, Fu said it was “a little disappointing” that Obama declined to make a statement about the situation.

“I understand President Obama has a delicate situation,” Fu said. “But I always wish the U.S. politicians would support, I mean, unequivocally for all those who are persecuted instead of trying to spare the feeling of the persecutors.”

ChinaAid, citing “a source close to the Chen Guangcheng situation,” said Sunday that Chen was under U.S. protection and that “high-level talks are currently under way between U.S. and Chinese officials” regarding his status.

The situation presents an extraordinary test for the Obama administration’s approach to relations with China, creating a strain between upholding human rights and maintaining steady ties with Beijing.

Clinton and Treasury Secretary Timothy Geithner are scheduled to hold talks with Chinese officials in Beijing starting Thursday about strategic and economic issues. But the Chen affair could overshadow the economic talking points.

“If Chen is holed up in the U.S. Embassy, it is hard to fathom how the two sides will stay focused on the many pressing geostrategic and economic challenges in the relationship,” Christopher Johnson, a China analyst at the Center for Strategic and International Studies in Washington, wrote in an opinion article for CNN.

The activist’s flight from detention comes at a highly sensitive time for Chinese authorities. The ruling Communist Party has been rocked by a scandal involving former high-ranking leader Bo Xilai, whose wife is under investigation in relation to the mysterious death of a British businessman in the southwestern metropolis of Chongqing.

The downfall of Bo, the former Chongqing party chief who is now being investigated in connection with serious disciplinary violations, has created shock waves ahead of a once-in-a-decade leadership transition in China that is due to unfold this year.

American and Chinese officials have declined to comment directly on the Chen case. But John Brennan, one of Obama’s national security advisers, said Sunday that the U.S. government was “working very closely with the individuals involved.”

The United States is aiming to strike the “appropriate balance” between its commitment to human rights and its diplomatic relationship with China, Brennan said on Fox News.

R. Nicholas Burns, who was an undersecretary of state for political affairs under George W. Bush, praised the Obama administration’s low-key handling of the matter. “I just think that the administration is right to try to handle this privately right now, because that does not put the Chinese in an embarrassing situation publicly,” he told CNN’s Christiane Amanpour.

“In the end, this will be a humiliation for China — that a human rights activist, a great man, someone whom we all admire, was able to escape house arrest, make his way to Beijing,” he said. “That’s going to put a big spotlight on the deficiencies of the Chinese system, on their outright violations of human rights and, I would think, in the end, this will be a defeat for China.”

Republican presidential contender Mitt Romney said in a statement Sunday that he hopes the U.S. government will “take every measure to ensure that Chen and his family members are protected from further persecution.”

Chen addressed Chinese Premier Wen Jiabao in a video posted Friday on YouTube, detailing “cruel” abuses he said he and his family had suffered at the hands of authorities during months of heavily guarded detention in their home.

“They broke into my house, and more than a dozen men assaulted my wife,” he said. “They pinned her down and wrapped her in a comforter, beating and kicking her for hours. They also similarly violently assaulted me.”

Journalists and supporters were prevented from visiting Chen during his house arrest. One of those supporters is Hollywood actor Christian Bale, who was roughed up by security guards while attempting a visit in December.

Chen, 40, rose to fame in the late 1990s thanks to his legal advocacy for what he called victims of abusive practices, such as alleged forced abortions, by China’s family planning officials.

A local court sentenced Chen to four years and three months in prison in 2006 on charges of damaging property and “organizing a mob to disturb traffic” in a protest, charges that his supporters called preposterous.

Since his September 2010 release from prison, he had been confined to his home along with his wife, mother and daughter.

Chen’s escape appears to have angered local officials holding him captive, with supporters saying that at least four members of his family have been detained.

In the YouTube video, the activist appealed to the Chinese premier to investigate his case and expressed concern about the welfare of his wife, mother and daughter.

“Although I’m free, my worries are only deepening,” he said. “They have been persecuting my family for a long time, and my escape would only prompt them into a mode of revenge.”

The authorities’ reaction also seems to have ensnared Chen’s supporters, especially those suspected of aiding his escape.

After speaking to CNN, Hu, the fellow activist, was taken away by police for questioning, his wife posted on Twitter.

Chen’s friend He Peirong disappeared Friday, shortly after speaking to CNN and other news organizations about the activist’s escape.

The last message she sent out, according to ChinaAid’s Fu, was that state security agents had arrived at her home in the eastern city of Nanjing.

“I’m not concerned about my own safety,” she told CNN. “I hope they’ll arrest me, not my friends.”