A Chinese court sentenced a veteran activist Friday to nine years in prison for inciting subversion, in what appears to be the most severe punishment handed down in a crackdown to prevent the spread of Arab Spring-style democratic uprisings.

Chen Wei was convicted of incitement to subversion over four essays he wrote and published online, said one of his lawyers. He was detained in February amid an extensive government crackdown in response to anonymous online calls urging Chinese to imitate protests in North Africa and the Middle East.

Attorney Liang Xiaojun said that the trial at a court in the city of Suining in southwestern China lasted about 2½ hours and that the sentence was handed down 30 minutes after the trial concluded.

Writer Chen Wei was convicted of incitement to subversion over four essays he wrote and published online, one of his lawyers said. (Submitted)"We pleaded not guilty. He only wrote a few essays," Liang said. "We presented a full defence of the case, but we were interrupted often, and none of what we said was accepted by the court."

Liang said that after the sentence was handed down, Chen said: "I protest. I am innocent. Constitutional democracy must win, autocracy must die."

The trial was the first time Chen's wife, Wang Xiaoyan, saw her husband since he was detained more than 300 days ago, and she said he looked like he had aged a lot. Wang denounced the punishment.

"He is innocent, and the punishment was too harsh," she said by phone from Suining. "The court did not allow him to defend himself, and he was completely deprived of his right to free speech. What's wrong with a person freely expressing his ideas?"

Chen, 42, previously served time for participating in the 1989 Tiananmen Square pro-democracy demonstrations in Beijing, where he was attending college. In 1994, he was sentenced to five years in prison for "counterrevolutionary propaganda and incitement," according to the court indictment for his subversion charge.

China jittery, researcher says

The sentence handed down to Chen on Friday appears to be the heaviest penalty meted out in relation to this year's crackdown, said Wang Songlian, a researcher with Chinese Human Rights Defenders, a Hong Kong-based advocacy group.

"This severe punishment against an activist caught up in the Jasmine crackdown shows how the Chinese government's nerves are still jittery," Wang said.

"All its latest moves, its attempts to control its microblogs, its crackdown on activists, show it is increasing tightening on freedom of expression and other civil liberties," she said.

Others rounded up in this year's crackdown who have been punished include Beijing activist Wang Lihong, who was sentenced to nine months in jail in September for staging a protest on behalf of other activists, and Yang Qiuyu, a Beijing activist who was sentenced to two years of re-education through labor.

China's Communist leadership, which does not tolerate any perceived challenge to one-party rule, was spooked early this year when anonymous online messages called for a Chinese "Jasmine Revolution" — the name of the uprising in Tunisia.

Amnesty calls news 'heartbreaking'

Even though few outright demonstrators responded to the protest calls, China launched one of its broadest campaigns of repression in years, rounding up dozens of bloggers, lawyers and intellectuals. Most have since been released.

Amnesty International said Chen's sentence was only the latest case of the government's use of the vague charge of inciting subversion against its political critics.

"It's heartbreaking news and clearly retaliation for Chen Wei's peaceful critique of the Chinese Communist Party," said Catherine Baber, Amnesty International's deputy director for Asia. "Chen Wei is a prisoner of conscience and should be released immediately."

Others jailed in recent years on the same charge include Chinese dissident and Nobel Peace Prize laureate Liu Xiaobo, for 11 years, and veteran activist Liu Xianbin, for 10 years.

Chen said before the trial that he would not appeal the sentence and is likely to stick to that, his wife said. "He doesn't want to join them in this pretense. There's no need to," she said.