Prominent Chinese activist Xu Zhiyong went on trial Wednesday over his role in anti-corruption protests but defied the court by refusing to speak, his lawyer said, calling the proceedings a "piece of theatre".
Xu, founder of the New Citizens Movement, faces a five-year jail term on charges of "assembling a crowd to disrupt order in a public place" for demonstrations featuring banners calling for asset disclosure by officials -- seen as a key measure against graft.
Dozens of police, in uniform and plain clothes, surrounded the court in western Beijing, harassing reporters outside the building.
Several Xu supporters said at least three protesters near the premises had been detained.
Xu's lawyer Zhang Qingfang told AFP he and his client had remained silent inside the court. "We don't want to take part in a piece of theatre, we are not actors, we can't act," he said.
"The court tried to persuade Xu to speak... and spent 10 minutes trying to persuade the lawyers to speak," Zhang added. "We will continue to remain silent."
Xu is one of eight New Citizens Movement activists -- including several businessmen and a lawyer -- due to stand trial this week in what has been viewed as part of a government crackdown on dissent.
They are all almost certain to be found guilty by China's politically controlled courts.
The trials come despite a much-publicised anti-corruption drive by China's Communist party under Xi Jinping, and overseas rights groups have condemned the proceedings as "hypocritical".
They may have been held separately just ahead of China's busy Lunar New Year holiday to decrease the risk of protests outside the court, lawyers said.
Despite this, at least 20 supporters from across China gathered nearby for Xu's hearing, with a group of around 10 unveiling a red banner calling for officials to disclose their assets -- similar to the actions which led to Xu's trial.
"If you don't expose your assets, it shows you must have a secret," said one of them, Wu Guangzhong. "Declaring assets is the most common way of preventing corruption."
Zhu Jiaqi, from Tianjin, added: "It should be an open trial but it's held in secret. Xu's voice reflects the voice of the basic and ordinary people."
Foreign diplomats were allowed into the court building, but were told they would not be permitted to attend the hearing itself, one European representative told AFP.
Between 20 and 40 people involved with the New Citizens Movement have been detained since last year, according to members, while at least three have previously been put on trial.
The arrests have been seen as part of a wider campaign to enforce ideological unity since Xi became the head of the Communist party in late 2012.
"The Chinese Communist Party reinforced its monopoly on power in 2013 through tough new measures and hardline rhetoric, dashing hopes that the country's new leadership would engage in deep systemic reforms to improve human rights and strengthen the rule of law," Human Rights Watch said in a statement this week.
Xu trained as a lawyer at one of China's top universities and became widely known in 2003 because of a campaign against a form of extra-legal detention.
He was at the core of an emerging group of "rights defence" lawyers, who sought to use legal arguments and court cases to push for political reform.
But Chinese authorities, who do not permit independent and organised forms of dissent, arrested him in 2009 on tax evasion charges, which were dropped months later after a public outcry.
In recent years Xu -- whose wife gave birth to a daughter this month -- lived under regular surveillance. He has been repeatedly detained and held under house arrest by state security agents, who even attended his wedding in 2011.
Standing outside the courthouse, Ma Zhurong from the northern province of Shaanxi praised Xu for helping people like her pursue individual justice.
"Xu Zhiyong is just someone who helped powerless people using the law," she said. "(He) wanted to speak up for those who suffered."
China activist Xu Zhiyong in silent protest at trial: lawyer