A well-known Vietnamese blogger, jailed for 12 years for anti-state propaganda, is "very weak" after a month-long hunger strike protesting at his treatment in prison, his family says.
Nguyen Van Hai - a founding member of the banned Free Journalists Club who is better known by his alias Dieu Cay - has not eaten for 30 days, according to his ex-wife Duong Thi Tan.
"He is very weak... He spoke softly and couldn't sit up unaided," she told AFP, following a visit to the prison by the couple's son on Saturday.
She said Dieu Cay went on hunger strike to protest against his treatment in a prison in central Nghe An province, adding that her son had been allowed to talk to his father for five minutes "before they dragged him away".
"He was kept in solitary confinement for three months when he did not violate any rule," she said, accusing the jail of having "extremely bad" conditions.
"He said he would continue the hunger strike if authorities do not respond to his complaint," Tan told AFP.
The family were "very worried" that the new hunger strike would endanger his health, she said.
Dieu Cay, whose case has been raised by US President Barack Obama, was sentenced in September 2012 along with two other bloggers who received jail terms of 10 years and four years.
The blogger has been on hunger strike once before for 28 days, in late 2011, also to protest at his treatment in jail. He ended up in hospital in Ho Chi Minh City before agreeing to end his fast.
Dozens of peaceful political activists have been jailed since Vietnam began a new crackdown on dissent in late 2009.
Vietnam bans private media and all newspapers and television channels are state-run. Lawyers, bloggers and activists are regularly subject to arbitrary arrest and detention, according to rights groups.
So far in 2013, at least 46 activists have been convicted of anti-state activity and sentenced to often lengthy jail terms under what rights groups say are vaguely defined articles of the penal code.
Earlier this month, prisoners in the Xuan Loc jail in Dong Nai province, about 40 kilometres north of Ho Chi Minh City rioted over conditions and treatment in jail.
In late June, high-profile dissident Cu Huy Ha Vu, serving a seven-year sentence for spreading anti-state propaganda, ended a three-week hunger strike to protest against his treatment in prison.