“I am pleased that we were able to facilitate Chen Guangcheng’s stay and departure from the U.S. Embassy in a way that reflected his choices and our values,” Clinton said.

She added: “Mr. Chen has a number of understandings with the Chinese government about his future, including the opportunity to pursue higher education in a safe environment.”

Teng Biao, a Beijing human rights lawyer and longtime colleague of Chen’s, expressed skepticism about the deal even before the latest details were known.

“His friends are very worried about his safety. If he leaves the embassy, then his safety has no guarantee,” Teng said. Asked about Beijing’s assurance of well-being for Chen, Teng replied: “I have no trust in it.”

The seeming resolution of Chen’s presence in the embassy at first appeared to have headed off what was expected to be tension during two days of high-level talks set to begin Thursday among Clinton, Treasury Secretary Timothy Geithner and their Chinese counterparts over a wide range of issues. But the suggestion that Chen had left the embassy under conditions that were less favorable than U.S. officials had said roiled Washington.

The Congressional-Executive Commission on China, a panel of members of Congress and Obama administration officials that monitors U.S. relations with China, announced that it would hold an emergency session Thursday.

Rep. Christopher Smith, R-N.J., the chairman of the commission, said he was concerned about Chen’s safety. "He’s in a precarious situation,” Smith said, describing himself as “disappointed” when he first heard the news that Chen had left the embassy.

"I said from the beginning, ‘Who is going to monitor this?’ " Smith said. " ‘How will it be enforced?’ China is not a safe place for any dissident."

Smith said he also wanted to know how insistent State Department officials had been in negotiating Chen’s departure and whether officials had pushed for a solution so as not to derail the planned talks on other topics.

"I hope they weren’t operating on a get the desk cleared so the more important things can take place" basis, he said. "Human rights should be the most important priority that we have."

State Department officials in Washington and Beijing said Chen’s departure from the embassy had been voluntary.

“We respected Mr. Chen’s free will, both his desire to depart the embassy, which he did . . . of his own free will, and most fundamentally his consistently stated desire to stay and work in his own country and to continue his work,” said one diplomat, who spoke to reporters on the condition that he not be identified.

The official, who was involved with the negotiations, said that Ambassador Gary Locke had asked Chen, “ ‘Are you ready to go?’ And he sat there and he said . . . ‘Let’s go.’ And he stood up and we walked out together.”

A second State Department official at the briefing said, “Throughout his stay at the embassy – and I’m talking about numerous discussions – Mr. Chen made it clear that he wanted to remain in China with his family, and, frankly, he wanted to participate with what he thinks is ongoing in China, which is a very exciting, dynamic period that he believes that he has an important role to play, as do we.”