Chen Guangcheng, the blind lawyer known for his outspoken opposition to China’s forced abortion and sterilization policies, has escaped from house arrest and has reportedly sought U.S. diplomatic protection, potentially casting the United States in an awkward position on the eve of high-level talks between the nations.

The exact whereabouts of Chen, who posted a dramatic YouTube video calling on Premier Wen Jiabao to investigate his case and protect his family from abusive police officials, were unclear early Saturday.

ChinaAid, a Texas-based activist group, said Chen was under the protection of U.S. officials and talks were underway between U.S. and Chinese officials about his fate. The U.S. Embassy, however, maintained its silence, declining to either confirm or deny that Chen was there, with a diplomat citing the sensitivity of the situation.

“Premier Wen, with great difficulty, I have escaped,” a grim-looking Chen, wearing dark glasses, announced in the video message. He detailed beatings that had been inflicted on him and his wife, injuring his wife’s back, ribs, elbow and eye, while being denied medical care.

Hu Jia, another prominent activist and friend of the Chen family, said Chen left his village in Shandong province Sunday night and arrived in Beijing on Monday. Hu said Chen was “in the U.S. Embassy or under the shelter of diplomats, at least.”

Neither the U.S. Embassy in Beijing nor the State Department would confirm or deny reports that he was at the embassy. That helped fuel rumors, including one that Chen was already on a plane bound for the United States, and possibly Washington’s Dulles International Airport. But a commercial flight that arrived Friday night at Dulles from Beijing did not appear to have Chen among its passengers.

If the U.S. government is aiding or sheltering Chen, it would be the first time the embassy in Beijing had played such a role since the crackdown on Tiananmen Square demonstrators in 1989, when astrophysicist and democracy advocate Fang Lizhi was given refuge at the embassy. He stayed there for about a year before China granted him permission to leave for medical reasons and settle in the United States. Fang, who later taught at the University of Arizona, died this month.

Chen’s escape and the YouTube plea to Wen seemed likely to embarrass the Beijing government just days before Secretary of State Hillary Rodham Clinton and Treasury Secretary Timothy F. Geithner arrive for long-scheduled talks on political and economic matters.

Clinton has repeatedly called for Chen’s release, yet his escape comes at a delicate time when Washington is trying to enlist Beijing’s help on a range of global issues, from containing the nuclear ambitions of Iran and North Korea to helping broker a cease-fire in Syria.

The Obama administration put up a wall of silence in the hours after Chen’s escape became public Friday morning. State Department spokeswoman Victoria Nuland, pressed repeatedly by reporters at the department’s daily news briefing, said only: “I don’t have anything for you on that subject.”

Asked more generally about China’s treatment of Chen, Nuland said, “We have always had concerns about this case.”

Chen ran afoul of authorities after he filed a class-action lawsuit in 2005 accusing officials of enforcing the one-child population law by forcing thousands of women to undergo late-term abortions and compulsory sterilization. He has been in and out of prison in recent years.

After his last prison release, in September 2010, he was taken to his farmhouse in Dongshigu village and kept under unofficial house arrest, surrounded by armed thugs in plain clothes who prevented Chen and his wife from leaving and blocked journalists and activists from visiting.

If Chen turns out to be sheltered by U.S. diplomats, it would present the Obama administration with the second thorny diplomatic issue with China in recent months. On Feb. 6, former Chongqing police chief, Wang Lijun, spent more than a day at the U.S. consulate in Chengdu.

In that case, Wang left the consulate — of his own volition, according to U.S. diplomats — and was immediately taken into custody by Beijing central government security officials, but only after revealing a tale of internal intrigue, scandal and murder that led to China’s biggest political crisis in two decades. Wang, who as police chief led an often-brutal anti-crime drive in Chongqing, is being held incommunicado by Chinese security agents as part of a wide investigation into purged Communist Party official Bo Xilai.

“There is a series of dots that connect up here with these embassy episodes where the United States keeps getting drawn into China’s internal affairs,” said Orville Schell, director of the Center on U.S.-China Relations at the Asia Society in New York. “With the Wang Lijun thing, the United States has been very prudent and careful to not say anything. That’s the proper response. But with Chen Guangcheng, there’s no way they can’t say something because you have Hillary Clinton heading over there.”

There are several examples of temporary refuge given at U.S. diplomatic installations around the world but “posts may not grant or in any way promise ‘asylum’ to any foreign national,” according to Foreign Service regulations. Asylum is granted only to applicants in the United States or at a port of entry.

Noting that the embassy buildings abroad are technically on U.S. soil, Frank Jannuzi, head of Amnesty International’s Washington office, said, “If he is on U.S. soil, it is incumbent on the U.S. government to provide for his safety and the safety of his family as well as those who helped him escape his unjust and illegal arrest.”

Jannuzi said that, no matter the legalities, the United States had a “moral obligation . . . to assure his safety and good treatment.”

Chen’s case has attracted attention, both inside China and abroad, because he had already served a 51-month sentence imposed after a sham trial on largely discredited charges of “obstructing traffic.”

On Nov. 10, before a meeting in Hono­lulu with China’s foreign minister, Clinton said, “When we see reports of lawyers, artists and others who are detained or ‘disappeared,’ the United States speaks up both publicly and privately.”

She added: “We are alarmed by recent incidents in Tibet of young people lighting themselves on fire in desperate acts of protest, as well as the continued house arrest of the Chinese lawyer Chen Guangcheng.”

Phelim Kine, senior Asia researcher for the group Human Rights Watch, said Chen’s case “highlights the yawning divide between the government’s often-lofty rhetoric about rule of law and the far grimmer reality endured by people like Chen, who challenge the status quo by merely seeking to access rights and freedoms guaranteed by China’s laws and constitution.”

Kine said Chen’s house arrest over the past 19 months amounted to “effectively a de facto and de jure kidnapping by elements of the security apparatus.”

Chinese dissidents and friends of Chen declined to identify anyone who met Chen in Beijing or to describe his movements after he arrived in the capital Monday. They said the video was made sometime from Monday to Thursday.

In his video message, Chen, seated before a white curtain, ­urges Wen to investigate corruption in his area.

“The money of our ordinary people and the taxpayers should not be used by some local officials who break the law to hurt people or hurt the image of our party,” Chen says. “Many people don’t understand whether all of these illegal acts are just law-breaking by the local party officials or whether it was ordered by the Central Committee. I think you should give a clear answer to people before long.”

A link to the video was sent to multiple Web sites, activists said, including Boxun.com, an overseas Chinese community Web site run from Durham, N.C. Watson Meng, 47, who runs the site, said that an activist in Beijing sent the video link to him via Skype and that someone in China had uploaded the video to Microsoft’s Live.com.

Separately, a friend of Meng’s in Beijing sent a Skype message to him that had come from activist Guo Yushan. “Dear Friends, Chen Guangcheng has left Shandong magically,” it said. “He is free at the moment. He is in a safe place.”

Mufson reported from Washington. Researcher Zhang Jie in Beijing and correspondent Andrew Higgins and staff writers Joby Warrick and Ellen Nakashima in Washington contributed to this report.