A prominent activist who publicised human rights abuses across China has gone on trial in the capital, Beijing.
Hu Jia faces up to five years in prison if convicted
Hu Jia, 34, is accused of "inciting subversion of state power and the socialist system".
The charges relate to interviews he gave to foreign media and political articles that he wrote for the internet, his lawyer Li Fangping said.
Mr Hu was detained late last year and then charged. His wife, also an activist, remains under house arrest.
Mr Hu went on trial at the Beijing Number 1 People's Intermediate Court.
Western diplomats who tried to enter the court were turned away, the Associated Press news agency reported.
Before his arrest, the activist had been an outspoken critic of China's record on issues like Aids, the environment and religious freedom. Correspondents say he had become a kind of one-man clearing house for information, passing it on to journalists, organisations and foreign embassies.
Hu Jia faces up to five years in prison if convicted.
Chinese Premier Wen Jiabao, when asked to comment on his case at a news conference at the close of parliament, said issues like this would be handled according to the law.
"As for critics' view that China is trying to increase its efforts to arrest dissidents ahead the Olympic Games, I think all these accusations are unfounded," he said.
US-based watchdog Human Rights Watch called on the Chinese government to drop the charges against Mr Hu.
"Hu Jia's case has been marked by grave rights violations from the outset," said Sophie Richardson, the group's Asia advocacy director.
"His arrest was political, the charges are political and his trial is political."