One of China's most prominent human rights lawyers has gone on trial in Beijing, amid scuffles outside court.
Pu Zhiqiang is accused of "inciting ethnic hatred" and "picking quarrels and provoking trouble".
Foreign journalists, diplomats and a small group of Chinese protesters were manhandled by security officials outside the court.
Mr Pu is the latest to be tried in a crackdown on lawyers, dissidents, and those accused of corruption.
He posted comments on social media mocking the ruling Communist Party and questioning policies towards Xinjiang's Muslim Uighur minority, as well as Tibetans.
Mr Pu has been in detention since May 2014, after he attended an event to commemorate the 25th anniversary of the Tiananmen Square crackdown. He participated in the Tiananmen protests as a student.
The BBC's John Sudworth, who is outside the court, says that given the government's tight control of the courts, there is almost no chance of an acquittal and Mr Pu likely faces a lengthy spell in prison.
Outside court, a US diplomat read out a statement saying that lawyers and civil society leaders in China should not be subject to "continuing repression" and called on Beijing to uphold rights enshrined in the country's constitution.
An EU diplomat was prevented from making a statement outside court. It said that the trial raised "serious questions of consistency with China's constitutional guarantees of freedom of assembly, opinion and expression," according to photographs of the statement posted on social media by reporters.
Diplomats from a number of countries were gathered outside court but reporters at the scene said officials would not allow any of them to enter.
International rights groups have described Mr Pu's case as political persecution. Amnesty International says there have been "repeated procedural irregularities'' in his prosecution.
Pu Zhiqiang represented artist Ai Weiwei in a tax evasion case that critics complained was politically motivated. He also campaigned for the eventual abolition of the labour camp system, under which suspects could be detained for years without trial.
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