(Updates with White House condemnation, paragraphs 9-10)
By Sui-Lee Wee
BEIJING, Jan 26 (Reuters) - A court sentenced one of China's most prominent rights advocates to four years in prison on Sunday after he campaigned for the rights of children from rural areas to be educated in cities and for officials to disclose their assets.
Xu Zhiyong's jailing will send a stark warning to activists that the Chinese Communist Party will crush any challenge to its rule, especially from those who seek to organise campaigns.
It also diminishes hopes for meaningful political change, even as China pledges to embark on economic reforms.
Separately, one of China's most prominent dissidents, Hu Jia, who frequently accuses authorities of infringing civil liberties, said police had summoned him on a charge of "suspicion of causing a disturbance".
The Beijing No. 1 Intermediate People's Court found Xu guilty of "gathering a crowd to disturb public order", the court said on its official microblog. Xu was tried on Wednesday.
Xu's lawyer Zhang Qingfang said he would meet Xu within the next two days to determine whether to lodge an appeal.
"He said (in court) that the last remaining dignity of the Chinese legal system has been destroyed," Zhang told reporters.
"It's not that we can't bear this result but that, fundamentally, the guilty conviction is illegal, is unreasonable and unfair."
The United States condemned the move.
"Chinese authorities should release Xu and other political prisoners immediately and live up to their international human rights commitments," President Barack Obama's national security adviser, Susan Rice, said via Twitter. She said she was "deeply disappointed" in Xu's sentence.
There were chaotic scenes outside the court as police shoved and harassed foreign reporters. Zhang was briefly taken away in a van by police after the hearing. He said police were still tailing him after he was released.
The government has waged a 10-month drive against Xu's "New Citizens' Movement", which advocates working within the system to press for change. Hundreds of citizens have participated in activities related to the movement, rights activists say.
"This is a shameful but sadly predictable verdict. The Chinese authorities have once again opted for the rule of fear over the rule of law," Roseann Rife, East Asia Research Director at Amnesty International, said in a statement.
"The persecution of those associated with the New Citizens Movement demonstrates how fearful the Chinese leadership are of public calls for change."
Hu, the dissident, said he was prepared to face detention.
"It's because I've participated in many street protests," Hu told Reuters by telephone as police waited outside his door to take him away.
"I've asked for officials to publicly disclose their assets and have expressed solidarity with those who've been arrested. I've appealed to many people to watch and promote these street protests."
Hu was jailed in 2008 for 3 1/2 years on subversion charges for criticising human rights restrictions. Some supporters saw him as a potential recipient of the Nobel Peace Prize before it went to another jailed Chinese dissident, Liu Xiaobo, in 2010.
China has detained at least 20 activists involved in pressing for asset disclosure by officials, although not all are from the New Citizens' Movement.
Two activists stood trial on Thursday in Beijing and four others will be tried on Monday. Three went on trial in December and face more than 10 years in prison if convicted. (Full Story)
"Instead of 'putting power' within a 'cage of regulations', as Xi Jinping has promised, the new leadership appears to be more interested in consolidating power," Brad Adams, Asia Director at Human Rights Watch, said in a statement.
"Staging show trials of critics is wholly at odds with Xi's self-proclaimed reformist agenda.".
Xu's verdict is also a rebuff to Western governments who have expressed concern about his case.
"We are concerned that today's conviction is retribution for Xu's public campaign to expose official corruption and for the peaceful expression of his views," said Daniel Delk, second secretary for the political section at the U.S. embassy.
Through his online essays and Twitter account, Xu pushed for officials to disclose their assets and also campaigned for the rights of children from rural areas to be educated in cities, where many live with their migrant worker parents.
Xu's trial is China's highest-profile proceeding against a dissident since 2009, when Nobel laureate Liu went on trial for subversion after helping organise the "Charter 08" petition urging the overthrow of one-party rule. He was jailed for 11 years.
During Xu's trial, the court rejected the 68 witnesses the defence had applied to testify. It also barred diplomats from attending.
Xu taught law at a Beijing university and ran in a local election. He became prominent over a drive to abolish "custody and repatriation" powers, a form of arbitrary detention used by local governments to sweep homeless and other undesirables from the streets. The government scrapped the system in 2003.
"I'm sad, words fail me. This is a great tragedy," said rights lawyer Teng Biao, a close friend of Xu. "In his promotion of the 'New Citizens' Movement' and other human rights activities, none of it constitutes a crime, so his trial and sentencing have no legal basis."
Du Guowang, an activist who was given legal advice by Xu in 2011 on equal education rights, said police have tailed him for nearly a week in a bid to prevent him from going to the courthouse to support Xu
(Additional reporting by Ben Blanchard and Jeff Mason; Editing by Paul Tait and Ron Popeski)