A blind legal activist and inspirational figure in China's rights movement fled the house arrest he has lived under and made it to a secret location in Beijing on Friday, setting off a frantic police search for him and those who helped him, activists said.

Chen Guangcheng's escape, if ultimately successful, would boost a beleaguered civil rights community, which has faced rising arrests and other harassment over the past year.

Activists described an improbable escape, saying Chen slipped away from his well-guarded rural village on Sunday night, driven away by activists and then transferred to others who brought him to Beijing.

By Friday afternoon, Chen "was 100 per cent in a safe location," said Bob Fu, an activist based in Texas who runs the China Aid Association and who was in contact with people helping Chen. But Chen's flight unleashed a police crackdown on his relatives and the people who helped him flee, activists said.

Escape could ignite 'violent revenge'

"I am now free. But my worries have not ended yet," Chen said in a video that was recorded this week and that activists sent Friday to the overseas Chinese news site Boxun.com, which then posted part of it on YouTube. It could not be independently verified. Speaking to a camera in a room with an off-white curtain drawn behind him, Chen said, "My escape might ignite a violent revenge against my family."

A self-taught lawyer blinded by fever in infancy, Chen served four years in prison for exposing forced abortions and sterilizations in his and surrounding villages. Since his release in September 2010, local officials confined him to his home, despite the lack of legal grounds for doing so, beating him up on several occasions.

Chen was widely admired by rights activists at home who — led by blogger He Peirong — last year campaigned to publicize his case among ordinary Chinese and encourage them to go to Dongshigu village and break the security cordon. Even Hollywood actor Christian Bale tried to visit, but as with many others he was roughed up by locals paid to keep outsiders away.

Why activists spirited Chen to Beijing was not immediately known.

Though China's most policed city, Beijing is home to foreign embassies that could provide asylum. Chen's mistreatment has often seemed to be a vendetta by local officials, and perhaps Chen and his helpers thought a direct appeal to the central leadership would help.

U.S. won't comment

The escape threatens to unleash a new wave of negative publicity for the authoritarian government when top leaders are already dealing with the fallout from the toppling of a former powerful politician, cashiered amid allegations of corruption, murder and abuse of power.

Online rumours and unconfirmed reports said Chen had sought protection at the U.S. or another foreign embassy. The U.S. Embassy declined comment, referring questions to the State Department, where a press officer was not on duty overnight. China's Foreign Ministry and police and government officials in Chen's home town either refused comment or did not answer telephone calls.

Police detained He, the blogger, who earlier Friday told The Associated Press that she had driven Chen from Dongshigu village on Sunday night out of Shandong province to "a relatively safe place." She handed him to another activist, who called Fu on Friday to say that he was about to be arrested but that Chen already was safe. Civil rights lawyer Li Fangping said state security agents questioned him Friday about Chen.

In Dongshigu, where authorities have posted surveillance cameras and checkpoints since Chen's release in 2010, local officials swarmed his brother's home on Thursday, activists said, detaining the brother and his son after a violent scuffle. The county government, however, said the nephew remained at large and is wanted for assault.

In the video, Chen condemned his treatment and that of his family, accusing local Communist Party officials by name. He called on Premier Wen Jiabao, seen by many Chinese as a reformer, to punish those responsible.

Much about escape untold

"Including party leaders, police and other civilians, around 90 to 100 people have been involved in the persecution of my family. I hereby request to you, Premier Wen, to start an investigation into this case," Chen said.

Much about how Chen eluded his usually vigilant captors remains untold. "Obviously, he got some inside help," said Fu, the Texas activist.

His escape seemed to go unnoticed for several days. A Washington-based activist blogger quoted Chen's nephew, Chen Kegui, as saying he heard his family members whispering that "Guangcheng's gone" on Thursday morning, according to a transcript provided by the writer, Cao Yaxue.

On Thursday night, Zhang Jian, chief of the town that oversees Dongshigu, led local officials to scale the wall surrounding a house belonging to the activists' relatives and his nephew, Chen Kegui, confronted them with a long vegetable knife, according to Cao and He.

Chen Kegui wounded Zhang and other officials, their accounts said. Chen and his father were detained by paramilitary police with electric batons while troops surrounded the family compound, Fu said.