Jailed Nobel peace laureate Liu Xiaobo marked his 55th birthday on Tuesday in a prison in northeast China, prompting renewed calls from rights advocates for his immediate release.
Liu was sentenced to 11 years in prison on Christmas Day last year on subversion charges after co-authoring Charter 08, a bold petition calling for political reform in one-party Communist-ruled China.
He was named the peace prize winner in October, sparking fury in Beijing, which equated the Oslo-based Nobel committee's decision with encouraging crime. A ceremony in Liu's honour was held in the Norwegian capital on December 10.
The Chinese Human Rights Defenders, an activist network based in Hong Kong, said it wanted to "take this opportunity to wish Liu Xiaobo a happy birthday and to once again call for his immediate and unconditional release".
The group recalled in a statement that Liu was spending his first birthday at the remote Jinzhou prison in the northeastern province of Liaoning, but had not been free to celebrate in the past two years.
In 2009, he was in a Beijing detention centre following his sentencing, and in 2008, he was under police surveillance outside the Chinese capital.
Rights groups have said that family visits to Liu at the prison have been suspended, despite the fact that a monthly visit is guaranteed under Chinese law.
Liu's wife Liu Xia remains under house arrest at her Beijing home, and CHRD said her phone and Internet connections remained blocked. AFP attempts to reach her by telephone on Tuesday were unsuccessful.
CHRD called for those restrictions on Liu Xia to be lifted.
"There is absolutely no legal basis for any of the measures taken against her by Beijing officials," the group said.
"CHRD is concerned that Liu Xia may continue to face illegal house arrest for an extended period of time, and we reiterate our call for an immediate end to her persecution."
Liu's lawyer Shang Baojun told AFP that he too was unable to reach Liu Xia.
"I can't get hold of her. I contacted her family last week. She's still in her house in Beijing -- she's well, but there's no new news," Shang told AFP by telephone.