Leading Chinese lawyer and activist Xu Zhiyong was sentenced to four years in prison on Sunday for gathering crowds to disturb public order, his attorney said, in a case human rights groups said made a mockery of China’s professed commitment to the rule of law and to fighting corruption.

“It’s an unjust sentence,” Xu’s attorney Zhang Qingfang told reporters who had gathered about a block from the heavily guarded courtroom in Beijing. “The last dignity of Chinese law has been damaged.”

Zhang was then led away by police and bundled into a police car.

The soft-spoken Xu is the founder of a peaceful grass-roots movement promoting citizens’ rights that had campaigned for equal rights to education for the children of China’s rural migrant workers, and, more controversially, for Communist Party officials to publicly disclose their assets.

His indictment had accused him of organizing and inciting people to unfurl banners, distribute leaflets, attract onlookers, make a racket and obstruct police officers from enforcing the law during a series of small protests in 2012 and 2013.

“Xu Zhiyong was very moderate, and was accused of bending over backwards to meet the other side,” said Maya Wang of Human Rights Watch. “This heavy sentence will be seen as a slap in the face for that group of activists who have tried to put out a moderate message.”

The U.S. Embassy expressed “deep concern” about Xu’s conviction and called for his release. “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,” spokesman Nolan Barkhouse said, calling it part of a pattern of arrests of those who challenge the Chinese government.

The trials of six other members of the New Citizens’ Movement began last week in Beijing, while a seventh, leading entrepreneur Wang Gongquan, was released on bail after confessing and conducting “profound introspection,” according to the court.

Xu, 40, had refused to mount a defense at the trial, which he said had been rigged. When Xu tried to read aloud a closing statement on Wednesday, the judge interrupted him after about 10 minutes to say his comments were “irrelevant,” according to Zhang. Foreign diplomats and journalists were barred from the trial.

Xu’s speech, which was later made available by his attorney and was widely circulated online despite authorities’ efforts to censor it, laid out a manifesto for peaceful, gradual change in China to promote citizens’ rights and to encourage democracy and the rule of law through “freedom, justice and love.”

In it, he detailed some of his efforts to protect “powerless” members of society, such as seeking adequate compensation for parents whose children had fallen ill because of adulterated milk powder in 2008 and pushing for changes to China’s strict household registration system, which forces migrant workers in the country’s cities to send their children back home to receive an education.

He argued he had remained reasonable, moderate and constructive in his efforts to promote peaceful change, but warned that social injustice was intensifying, corruption becoming more rampant and the wealth gap between the elites and the general public widening.

Xu’s speech made reference to his Christian faith and to birth of his first child, a daughter, on Jan. 13.

“My decision comes at a time when my child has just been born, when my family needs me most, and when I yearn to be there by their side,” he wrote. “After years now of witnessing the bitter struggles of the innocent and downtrodden, I remain unable to control my own sorrow — or, try as I might, to remain silent.”

“When hopes of reform are dashed, people will rise up and seek revolution,” he said. “Peaceful transition to democracy and constitutionalism is the only path the Chinese nation has to a beautiful future.”

Wang, from Human Rights Watch, said Xu’s trial and sentence underlined increasing intolerance for dissent since Xi Jinping took over as president last year, and the hypocrisy inherent in Xi’s supposed commitment to fight corruption.

Chen Min, a columnist and fellow member of the New Citizens’ Movement, said the verdict was “sinful.”

”Reform cannot be done without sacrifice. Xu as a pioneer, he is willing to sacrifice himself to prevent further sacrifice of others,” he said by telephone from Taiwan, sobbing as he spoke. “This sentence cannot beat him down, cannot beat down the New Citizens’ Movement, either.”

The Beijing Intermediate Peoples Court published an article on social media that accused Xu of belonging to a group of lawyers who are “very ideological, politicized, and keen to mobilize public opinion” and whose loyalty to the law was gradually being subsumed by “political passion.”

“Teaching a Chinese court how to judge, and using its ‘international image’ to threaten China, is very old-fashioned,” the court argued, addressing its comments to the “Western public.”

Li Qi and Rongkun Zhao contributed to this report.