Chinese activist Chen Guangcheng called in Thursday to a hearing on Capitol Hill at which senior House Republicans criticized the Obama administration’s handling of the negotiations that preceded Chen’s departure from the U.S. Embassy in Beijing this week.

Earlier in the hearing, Rep. Christopher Smith (R-N.J.), who heads the Congressional-Executive Commission on China , had quoted Chen as saying he was “very disappointed” in U.S. officials and said he would seek to find out during a hearing next week whether their approach to the talks was affected by a desire not to let Chen’s case disrupt a visit to Beijing by Secretary of State Hillary Rodham Clinton and Treasury Secretary Timothy F. Geithner.

Later, Chen himself called Bob Fu, a rights activist with the Texas-based Christian group ChinaAid who was testifying at the hearing. The dissident lawyer, who is under watch by Chinese authorities in a Beijing hospital, reached Fu on his cellphone and addressed the room over speakerphone. Fu translated as Chen thanked those present for past efforts on his behalf.

“The thing I am most concerned about right now is the safety of my mother and my brothers,” Chen added, according to Fu.

Smith promised Chen help. “We will be unceasing in our efforts to secure your freedom,” he said.

Chen left the U.S. Embassy on Wednesday, six days after fleeing de facto house arrest in his village, and joined his wife and children at a local hospital. He remains there under the control of Chinese police and security authorities, despite efforts by U.S. diplomats to meet with him and Chen’s reported desire to seek asylum.

Rep. Frank Wolf (R-Va.), too, said White House officials had questions to answer.

“The most generous read of the administration’s handling of the situation was that it was naive,” Wolf said, adding that he planned to review all the cable communications — classified and not — pertaining to the Chen deal.

Smith said he had tried to place a call to Chen on Tuesday, after hearing that the dissident lawyer wanted to speak to him, but that a U.S. official did not connect him. After the unnamed U.S. official said Chen would call him back, the call never came, Smith said.

Smith added that the administration must answer a number of questions, including how any agreement to keep Chen and his family safe in China might be enforced, how the United States would respond if they experience retaliation, and the fate of Chen’s nephew, Chen Kegui, who was reportedly taken into custody after his uncle’s escape.

“The Obama administration has a high moral obligation to protect Chen and his family,” Wolf said. “To do anything less would be scandalous.”

Michael Horowitz, a senior fellow at the Hudson Institute, told those on the mostly empty dais that the diplomats in Beijing deserved “an F on bargaining.” The hearing was called only Wednesday, during the congressional recess, and no Democrats were in attendance.

Other witnesses stopped short of criticizing the administration outright on Chen, but urged further action.

Sophie Richardson, China director for Human Rights Watch said Clinton and Geithner should demand a meeting with Chen. “It is incumbent on the U.S. government to insist on access to him,” she said.

However, if Chen does decide to remain in China, she said, U.S. officials should monitor him closely to ensure that the Chinese government does not retaliate.

Horowitz said Congress should urge the administration to act quickly to open up the Internet in China, allowing citizens access to information that is now blocked.

“We have it within our means . . . to tear down the Internet firewalls that are the real source of the government’s ability to isolate its people,” Horowitz said. “Let’s honor and protect this man by tearing down the Internet firewalls.”

Fu, who said he had been in touch with Chen and his intimates earlier in the week, gave the lawmakers an account of what had happened to Chen before he left the U.S. Embassy. Fu said Chen told him that while he was at the embassy, U.S. officials had relayed to him a threat by the Chinese government: If he remained under U.S. protection, he would never see his wife and children again.

“After hearing that message by the Chinese government, conveyed by the U.S. official, his heart was heavy and [he] felt like he had no other choice,” Fu told the lawmakers.

U.S. officials have given a different account of events, denying that they relayed threats to Chen while he was at the embassy.

“At no time did any U.S. official speak to Chen about physical or legal threats to his wife and children,” State Department spokeswoman Victoria Nuland said Wednesday. “Nor did Chinese officials make any such threats to us.”