BEIJING — Liu Xiaobo, the Beijing writer who was given an 11-year prison sentence on subversion charges on Dec. 25 after urging Chinese leaders to embrace democratic reforms, appealed his conviction to the Beijing Supreme People’s Court on Monday, according to one of his lawyers.

The lawyer, Shang Baojun, told The Associated Press that Mr. Liu told him during a meeting that he had filed the appeal. “We are making an effort to defend his innocence, but we have no idea whether it will be successful,” Mr. Shang said.

Mr. Liu’s sentence, judged by many analysts to be unusually harsh, has drawn criticism from human rights groups, Western governments and writers worldwide. Most regard the chances that it will be overturned or softened as slim.

Mr. Liu, 53, was seized by security officials in December 2008 as he and other intellectuals prepared to issue Charter 08, a lengthy manifesto that called on China’s Communist Party to uphold individual rights and relinquish its monopoly on power. After being held more than a year in secret detention and later in jail, Mr. Liu was found guilty by a Beijing court on Dec. 25 of “inciting subversion of state power.”

More than 300 intellectuals and activists signed the charter, which was drafted in part by Mr. Liu. More than 10,000 others since have added their signatures to the document, which appeared briefly on the Internet before Chinese censors banned it.

Legal experts said the 11-year prison term, the lengthiest handed down for subversion in at least a decade, was intended to send a signal to other dissidents that Chinese leaders would tolerate no challenge to the Communist Party’s 60-year control of state power.

China’s state-controlled news media have made no mention of Mr. Liu’s arrest, trial or sentencing. The government news agency Xinhua issued a statement after Mr. Liu’s sentencing declaring that the government had followed Chinese legal procedures in the case and that it had protected Mr. Liu’s rights.

Source: Michael Wines, The New York Times