The Chinese dissident Chen Guangcheng is safe in US custody according to a human rights group.
US-based ChinaAid confirmed that high-level talks between Chinese and US officials are underway.
The group said in a statement it had "learned from a source close to the Chen Guangcheng situation that Chen is under US protection" in Beijing.
"This is a pivotal moment for US human rights diplomacy,” said Bob Fu, ChinaAid President.
"Because of Chen's wide popularity, the Obama Administration must stand firmly with him or risk losing credibility as a defender of freedom and the rule of law. If there is a reason why Chinese dissidents revere the US, it is for a moment like this."
The US embassy's involvement in the matter could raise tensions between Beijing and Washington, a week before Secretary of State Hillary Clinton is due to visit the Chinese capital.
Mr Chen, a prominent human rights activist and dissident, escaped from house arrest in a daring night-time escape.
The blind activist evaded almost 90 guards who were stationed around his house and in his village for over a year.
There are now fears for the safety of Mr Chen’s family members and friends.
The Chinese Human Rights Defenders (CHRD) group said they believed four of his relatives had already been detained.
"We're very concerned that authorities appear to have launched a round of retaliation against Chen's family, relatives and activists who assisted Chen Guangcheng's flight for freedom," said Renee Xia, international director of the CHRD.
UN Human Rights Chief Ms Navaneetham Pillay also expressed concern about the welfare of Mr Chen’s family in a statement.
“I’m disturbed to hear reports that other family members, including his brother Chen Guangfu and nephew Chen Kegui, have now been detained,” Pillay said.
The High Commissioner said she has previously raised concerns with the Chinese authorities over Chen Guangcheng's case, and once again urged them “to investigate the treatment of both him and his family, to ensure their physical integrity, and to provide redress for any wrongdoing by local officials.”