A United Nations human rights body denounced on Friday the detention of one of China's best known human rights lawyers, Gao Zhisheng, urging the government to release him.
A Beijing court sent Gao back to jail earlier this month, though he appears never to have escaped secretive confinement in the first place.
"It is alarming that Mr. Gao continues to be arbitrarily detained. His detention over the years has resulted in various human rights violations, including his fundamental right to a fair trial," El Hadji Malick Sow, chair-rapporteur of the U.N.'s Working Group on Arbitrary Detention, said in a statement.
"I urge the authorities to release Mr. Gao."
A combative rights advocate who tackled many causes anathema to the ruling Communist Party, Gao was sentenced to three years' jail in 2006 for "inciting subversion of state power," a charge often used to punish critics of one-party rule.
Gao was given five years' probation, formally sparing him from serving the prison sentence. But Gao was detained on and off over that time.
He was taken from a relative's home in Shaanxi province in northern China in February 2009 -- his family claims by security officers -- and had been missing since early last year, when he resurfaced briefly and made sporadic contact with friends and foreign reporters in April 2010.
Gao's case has attracted international attention.
Chinese Foreign Ministry spokesman Liu Weimin told reporters in Beijing on Friday that China did not want "other countries interfering in its domestic affairs or legal sovereignty" when it came to Gao.
Starting in February, China mounted a crackdown on potential political challengers to the ruling Communist Party, fearing that anti-authoritarian uprisings in Arab countries could inspire protests against one-party rule.
Human rights advocate Chen Wei was sentenced to nine years in jail by a court in southwest China after a brief hearing on Friday in which he pleaded not guilty to subverting state power, the stiffest punishment in a crackdown on dissent this year.