HONG KONG—Human rights groups and a prominent Chinese American author are calling on the Chinese government to release dissident and writer Liu Xiaobo, who drafted a document last year calling for a radical overhaul of China’s political system.

Emily Wu, author of an English-language memoir about growing up during China’s turbulent 1958 Great Leap Forward and Cultural Revolution (1966-76) titled Feather in the Storm, said she and fellow members of the authors’ group Independent Chinese PEN, which Liu helped to found, were shocked and angry to hear Liu had been charged with incitement to subvert state power.

“[We] are both shocked and angry,” Wu said. “The Communist Party has gone mad.”

“All he was doing was using his conscience to do some thinking on behalf of his country and people,” she said. “They locked him up for more than six month on no charges whatsoever.”

The Beijing Municipal Public Security Bureau said in a statement this week that Liu, 53, was formally arrested Tuesday upon the approval of the procuratorate, the state prosecutor. Liu could face up to 15 years in jail.

“Liu has been engaged in agitation activities, such as spreading of rumors and defaming of the government, aimed at subversion of the state and overthrowing the socialism system in recent years,” said the statement, published in English by the official Xinhua news agency.

It said Liu had “confessed” to the facts of the case, without giving details.

Outcry over arrest

The U.S. Embassy in Beijing said Washington was “deeply disturbed” by the arrest and called on Beijing to respect the rights of those who peacefully criticize the government.

Rights groups and activists issued a joint open letter saying that the government had “acted in a weak, cowardly, and uncertain manner,” and its charging of Liu was “just a pretext to intimidate public opinion.”

“Who would have guessed that today, the government would go so far as to lose all reason and brazenly order his formal arrest,” said the letter, distributed by U.S.-based Human Rights in China and signed by “Tiananmen Mother” Ding Zilin and husband Jiang Peikun.

Beijing-based Liu was detained and his home searched ahead of the publication online of “Charter 08” on Dec. 8, 2008, a lengthy document calling for freedom of expression and association, free elections, and removal of the ruling Communist Party from control of the armed forces.

Liu’s wife Liu Xia said the police had told her that top civil rights lawyer Mo Shaoping wouldn’t be allowed to represent her husband at any forthcoming trial.

“They hemmed and hawed, and then said that because Mo Shaoping’s name appeared in some of the case materials, it wouldn’t be appropriate for him to be Liu Xiaobo’s attorney,” she said.

Two other lawyers had been appointed to defend Liu from the same chambers as Mo, Liu Xia said, and police had 48 hours to respond to their request for a meeting with him.

Meanwhile, Emily Wu said international writers’ groups would continue to press for Liu’s release.

“We will work through International PEN, American and Canadian PEN, and other PEN societies to send out news releases to media organizations around the world, calling on them to take notice of Liu’s case,” Wu said.