China's most prominent dissident, Liu Xiaobo, was jailed on Friday for 11 years for campaigning for political freedoms, with the stiff sentence on a subversion charge swiftly condemned by rights groups and Washington.

Liu, who turns 54 on Monday, helped organize the Charter 08 petition which called for sweeping political reforms, and before that was prominent in the 1989 pro-democracy protests centered on Tiananmen Square that were crushed by armed troops.

He stood quietly in a Beijing courtroom as a judge found him guilty of inciting subversion of state power for his role in the petition and for online essays critical of the ruling Communist Party, defense lawyer Shang Baojun said.

Liu was not allowed to respond in court to the sentence.

Xiaobo and I were very calm when the verdict was read. We were mentally prepared for it that he would get a long sentence, said Liu's wife, Liu Xia, who was allowed in to hear the verdict. She was barred from the trial on Wednesday.

Later we were allowed 10 minutes together, and he told me he would appeal, even if the chances of success are low, she said.

Liu has been among the most combative critics of China's one-Party rule. His case attracted an outcry from Western government and rights activists at home and abroad. The unusually harsh sentence drew a fresh outcry that is likely to grow.

China sees Liu Xiaobo as a representative figure, and think they can scare the others into silence with such a harsh sentence, said dissident writer and Christian activist Yu Jie.

President Hu Jintao believes that with the West weakened and human rights taking a back seat, he can ignore pressure over attacks on freedom of expression.

Standing outside the Beijing No. 1 Intermediate People's Court, a U.S. diplomat said Washington was deeply concerned.

We continue to call on the government of China to release him immediately and to respect the rights of all Chinese citizens to peacefully express their political views in favor of universally recognized fundamental freedoms, the diplomat said.

United Nations High Commissioner for Human Rights Navi Pillay said in a statement that the verdict cast an ominous shadow over China's commitments to protect human rights.

The conviction and extremely harsh sentencing of Liu Xiaobo mark a further severe restriction on the scope of freedom of expression in China, she said.

China, emboldened by its strong economy and the woes of Western powers, appears to have little patience with pressure over its strict controls on citizens' political activities.

China's Party-controlled courts rarely acquit defendants, especially in politically sensitive cases.

At the trial on Wednesday, the court limited Liu and his lawyers to 14 minutes to defend him -- the same time prosecutors spent laying them out the charges, said the lawyer Shang.

This created serious inconvenience for us, he said.

The verdict, which Liu's wife showed to a Reuters reporter, focused on his role in organizing Charter 08.

Liu had the goal of subverting our country's people's democratic dictatorship and socialist system, read the verdict. The effects were malign, and he is a major criminal.

China had criticized Western diplomats, who sought to attend the trial. The envoys were also excluded from the verdict hearing, as were reporters who gathered outside.

Amnesty International and Human Rights Watch decried the verdict. Online supporters and sympathizers displayed yellow ribbons in solidarity.

Local Chinese-language media did not report the verdict, but word swiftly spread on Twitter, which is blocked but can be accessed by by-passing Internet controls.

Liu has been a thorn in the government's side since joining a hunger strike backing Tiananmen student protesters. He had been jailed for 20 months after 1989, spent three years at a labor camp in the 1990s and months under virtual house arrest.

If Liu can be sentenced for his writings, then many more of us can also be sentenced, said Yu, the dissident.