China sentenced a prominent dissident and longtime U.S. resident to five years in prison on Thursday despite repeated appeals for his release by Congress, the Bush administration and human rights groups.

Yang Jianli, 40, who runs a foundation in Boston that advocates democratic reform in China, received the sentence immediately after being convicted by a Beijing court of spying for Taiwan and entering China on a false passport, the official New China News Agency reported.

Yang denied the charges during a closed-door trial in August. He was detained in 2002 when he returned to China after more than a decade in exile in the United States.

Yang's case has generated strong support in the United States, where he earned doctorates in political economy at Harvard's Kennedy School of Government and in math at the University of California at Berkeley. Yang is a permanent resident of the United States, and his wife and two young children are citizens.

Senior Bush administration officials have pressed for Yang's release in meetings with Chinese leaders, and both the House and the Senate unanimously passed resolutions urging China to free him. Last month, on the second anniversary of Yang's detention,67 members of Congress signed a letter to President Hu Jintao calling his treatment "extraordinarily inhumane."

"I'm saddened beyond words," said his wife, Christina Fu, by telephone from Boston. "Although I realize that things could be worse, five years is still very heavy on our family and our children and also for his parents."

Jared Genser, a family attorney, said he hoped the Chinese government would react to international pressure by deporting Yang, as it has other prisoners. He urged the State Department to file a strong protest in Beijing and asked members of Congress to contact the Chinese ambassador in Washington. "These next couple of days are critical," Genser said.

Yang fled to the United States after taking part in the 1989 pro-democracy demonstrations in Tiananmen Square and was exiled. But in April 2002, he used a friend's passport to return to China and observe large-scale labor protests in the northeastern part of the country.

Police arrested him and charged him with entering China illegally, a crime that carries a maximum one-year prison term. Prosecutors later accused him of spying for Taiwan, the self-governing island that Beijing claims is part of China.

Yang is the latest in a series of Chinese living overseas who have been arrested upon returning to the mainland and then convicted of spying for Taiwan with little or no evidence presented in public. His attorneys said China violated its own laws by holding him without trial for 14 months and waiting more than nine months after the trial to issue a verdict.

When Yang protested his detention last month by refusing orders to fold his blanket, wear a uniform or answer when addressed by his prisoner number, he was placed in solitary confinement with his wrists handcuffed behind his back until they bled, Genser said.

A spokesman for the Foreign Ministry, Liu Jianchao, defended the government's handling of the case, saying Yang was allowed to present a full defense in court. "The Chinese judicial departments have been trying this case and made a sentence in accordance with the law," Liu said.

Yang Jianli returned to China in 2002 to observe large-scale labor protests.