BEIJING — In a series of dramatically conflicting developments on Wednesday, the Chinese dissident Chen Guangcheng left American custody under disputed circumstances, and what briefly looked like a deft diplomatic achievement for Secretary of State Hillary Rodham Clinton turned into a potential debacle.

Mr. Chen, who was inside the American Embassy compound here for six days as the Chinese and American governments negotiated over his fate, left Wednesday afternoon in a deal that American officials hailed as a breakthrough because it would fulfill his wish to live safely in China.

But even as Americans were releasing photographs of a celebratory send-off of Mr. Chen from the embassy, his friends questioned the reliability of any Chinese promises to allow him to live openly in China, and Mr. Chen later said his decision to give up American protection had not been fully voluntary.

In a telephone interview Thursday morning from his bed at Chaoyang Hospital here, where he was receiving treatment as part of the deal between the Americans and Chinese, Mr. Chen, a lawyer who is blind, said he had left the embassy on his own volition after the Chinese government guaranteed that his rights would be protected. But he also said he had felt some pressure because he was told that Chinese officials had threatened to beat his wife to death if he remained under American protection.