One of China's most prominent human rights activists was taken into custody by police on Tuesday at his home, where he spent the last three months under house arrest.
Xu Zhiyong's detention on charges of having "gathered crowds to disrupt public order" followed a summons delivered earlier on Tuesday. The arrest deals a heavy blow to the New Citizen movement as dozens of fellow activists have also been arrested in the last months.
The outspoken law lecturer at Beijing University of Posts and Telecommunications is the most prominent representative of the movement, which has been calling for government transparency and respect of individual rights guaranteed by the Chinese constitution.
Lawyer Liu Weiguo, who represents Xu, said he would seek to visit the scholar at the No 3 Detention Centre in Beijing on Thursday.
Liu said he rejected the charges against Xu.
"How can a man who has been held under house arrest disrupt public order?" Liu said. "Xu has always been a moderate citizen who has never advocated violence in his writings. He has just availed himself of his right of freedom of speech as an ordinary citizen."
Teng Biao, a Beijing-based law scholar and personal friend of Xu, said the arrest was likely some time in the planning. "They arrested people around him to prepare for his arrest," he said.
Teng said he knew of 10 people who were arrested in Beijing - and many more in the provinces - on charges related to activities of the New Citizen movement.
In June, the Supreme People's Procuratorate issued a chilling notice calling on prosecutors to "resolutely crack down on activities of illegal assembly and crowds disturbing public order with the objective of subverting state power".
Charges of subversion of state power are often used to put dissidents in jail. Nobel Peace Prize laureate Liu Xiaobo is serving a sentence on such charges.
The notice called on prosecutors to use "their political wisdom and criminal strategy in striving to achieve legal effect in such cases".
Xu's detention comes days ahead of the expected first hearing in the trial of three movement activists in Xinyu, in southeastern China's Jiangxi province, on similar charges. They had been taken away from their homes in April and formally charged in June.
"They are cracking down on the gongmeng movement," said a person active in the movement from Hunan province, referring to the New Citizen movement. "With Xu, they are arresting one of the leading participants."
The person said that around October last year, activists in his home province started co-ordinating meetings across the country to discuss constitutional rights and government transparency over dinner.
In a blog post in late May 2012, Xu wrote a pamphlet arguing that China "needed a new citizens' movement" that established a "a free China that is democratic and ruled by law". In April this year, he was pulled from a flight to Hong Kong and has subsequently been barred from leaving his home in Beijing.
Half a decade ago, Xu was among the first activists to expose illegal detention centres, or "black jails", in Beijing.
Correction: the story was updated at 11am July 18 to correct the following errors:
Xu was detained pending a criminal investigation, instead of formally arrested; prior to his detention he had spent 3 months, instead of 2 months, under house arrest; in the 4th paragraph, Xu's lawyer's name should be "Liu Weiguo" instead of "Wang Weiguo."