Hu Jia's case has attracted considerable international attention
The decision by a Chinese court to jail a prominent human rights activist has sparked criticism from Western leaders and rights groups.
Hu Jia, 34, was jailed for three and a half years on Thursday for subversion.
US Secretary of State Condoleezza Rice called it "deeply disturbing", while UK counterpart David Miliband said it was "a most concerning development".
Amnesty International called it "a warning" to Chinese activists who raised human rights concerns publicly.
Earlier this week, the rights group accused China of a "wave of repression" against activists and dissidents ahead of the Beijing Olympic Games.
'Irrational and unfair'
Hu Jia has become one of China's most outspoken activists, tackling issues including religious and political freedom, HIV/Aids and the environment.
He was detained late last year, after weeks of house arrest, and convicted on Thursday of "inciting subversion of state power and the socialist system".
His lawyer said that charges related to interviews he gave to foreign media and political articles that he wrote for the internet.
Zeng Jinyan said the couple had been harassed
Chinese state media said that Mr Hu has been treated "with leniency" because he had acknowledged wrongdoing.
Foreign Ministry spokeswoman Jiang Yu said that his case had been handled "according to Chinese laws " and urged people not to interfere in China's internal affairs.
But Hu Jia's sentence was swiftly condemned in other areas.
"There is no doubt that this is a decision that is deeply disturbing to us and we are communicating that to the Chinese authorities," Ms Rice said at a Nato summit in Bucharest.
Louise Arbour, the United Nations High Commissioner for Human Rights, expressed concern about cases including Hu Jia's "in which it seems national security issues are being used as grounds to curtail social activism by human rights defenders".
Paris-based media watchdog Reports Without Borders, meanwhile, said it was "appalled".
The group urged European Union leaders to freeze human rights dialogue with China and called on leaders to boycott the opening ceremony of the Beijing Games.
Hu Jia's wife, Zeng Jinyan, is also a human rights activist. She remains under house arrest but was allowed to attend the court hearing for the verdict.
She said that her husband's imprisonment came after years of harassment.
"He's been under surveillance, been kidnapped. He's been put under house arrest and now they have sentenced him to three and a half years," she said. "This is irrational and unfair."
Hu Jia has 10 days in which to lodge an appeal against his sentence, but his lawyer said no decision on whether to do so had been made.