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Still, high-level talks between U.S. and Chinese officials began as scheduled on Thursday, indicating Mr. Chen's situation hasn't broadly disrupted relations. U.S. Secretary of State Hillary Clinton and Treasury Secretary Timothy Geithner were in Beijing for talks with Chinese Vice Premier Wang Qishan and State Councilor Dai Bingguo.

In her opening remarks to the talks in Beijing, Mrs. Clinton didn't mention Mr. Chen by name, though she more broadly brought up the issue of human rights in China. "A China that protects the rights of all its citizens will be a stronger and more prosperous nation, and of course, a stronger partner on behalf of our common goals," she said.

Mr. Chen has said in interviews that he felt pressured by U.S. officials to agree to the deal to leave the embassy and became fearful for his family's safety since he left the embassy's protection. The deal was criticized by human-rights activists and by some Republican lawmakers who said the U.S. couldn't guarantee his safety in China.

On Thursday U.S. Ambassador to China Gary Locke denied that Mr. Chen was pressured. "I can tell you unequivocally that he was never pressured to leave," he told a news conference. Mr. Chen made it very clear at the U.S. Embassy that he wanted to stay in China, Mr. Locke said, adding that Mr. Chen "knew the stark choices in front of him."

Mr. Chen left the U.S. Embassy's protection on Wednesday and was receiving medical treatment at Beijing's Chaoyang Hospital for a foot injury he sustained during his escape from Chinese authorities on April 22. Mr. Chen, who spoke briefly with The Wall Street Journal on Thursday before the phone connection was dropped, said he is in good health "but my heart is tired." Security personnel at Chaoyang Hospital denied entry by reporters on Thursday.

Under the deal unveiled by U.S. officials Wednesday, Mr. Chen would be allowed to unite with his family and move far away from his home in eastern Shandong province, where local authorities have kept him under virtual house arrest for 19 months without trial or charges against him. China had also agreed to refrain from retribution against those who had helped Mr. Chen make his escape from local authorities and brought him to Beijing.

But China appeared to be ramping up pressure on Mr. Chen's supporters, according to activists and human-right groups. "The fact that the Chinese government is continuing apace in pursuing the friends and relatives of Chen Guangcheng is an extremely worrying indicator in terms of how they're going to handle Chen Guangcheng's situation going forward," said Phelim Kine, senior Asia researcher for Human Rights Watch.

Activist Zeng Jinyan was taking her young daughter to school on Tuesday morning when public security agents who had been following her in a black car informed her she would be confined to her home, she said in a post on her Twitter account. "We will do our utmost to see to it that your daughter is picked up and dropped off and do our utmost to see to your daily needs. You cannot go out for these next few days," she quoted the agents as saying.

Ms. Zeng had been among the first to cast doubt on the deal for Mr. Chen's release, saying on Twitter on Wednesday that Mr. Chen and his wife had told her Mr. Chen was willing to leave China with his family but left the embassy out of fear for his family's safety. Ms. Zeng couldn't be reached to comment Thursday.

Human-rights lawyer Teng Biao, another friend instrumental in relaying Mr. Chen's anxieties Wendesday night, also appeared to be feeling pressure Thursday. "Please friends in the media, don't call me anymore," he wrote on his Twitter account. "I'm thinking of the safety of Chen Guangcheng's family and the safety of my own family."

Meanwhile, authorities continued to stay silent on a number of Mr. Chen's friends and extended family members who went missing after his escape.

He Peirong, a Nanjing-based activist who had been instrumental in aiding Mr. Chen's escape, has been missing since public security agents showed up at her door last Friday, according to other activists. Also missing since Friday are Mr. Chen's brother, sister-in-law and nephew. The nephew, Chen Kegui, was at one point believed to have been on the run from police after local authorities issued a statement saying he had attacked officials with a knife.

Yuan Weiguo, a Shandong-based lawyer who had agreed to defend Chen Kegui, recently told The Wall Street Journal that he had been forced to step back from the case, without elaborating.