BEIJING -- A Chinese writer and social critic has been sentenced to three years in prison for subversion after posting articles on the Internet criticizing the ruling Communist Party, his lawyer said Saturday.

Chen Daojun was convicted by a court in southwest China's Sichuan province on Friday after a 30 minute trial, his lawyer Zhu Jiuhu told Agence France-Presse.

"He was sentenced to three years in prison for the crime of inciting the subversion of state power," Zhu said.

"The prosecution used three of Chen's online articles criticizing the Communist Party and government as evidence of his guilt."

Chen was originally charged with the crime of "inciting succession" due to an article he wrote that supported anti-China protests which swept through Tibet in March, but that charge was dropped, Zhu said.

"His article expressing support for the Tibetan protests was not used as evidence in the trial," Zhu said.

The prosecution had earlier cited Chen's article "The Government Forces the People to Rebel: a Tribute to the Tibetans who Staged a Heroic Struggle," as evidence of inciting succession.

It was not clear why the court chose to change the charges against Chen, he said.

Chen, 40, was detained in May at his home in Chengdu city, the capital of Sichuan province, according to the Chinese Human Rights Defenders, a rights group in China that is largely organized through the Internet.

"The Chinese Human Rights Defenders believes that Chen has been imprisoned solely for the peaceful activities of expressing his opinions," the group said in a statement.

"We call for Chen's immediate and unconditional release."