Chinese authorities have prevented another top human rights lawyer from leaving the country, as he tried to board a plane for the democratic island of Taiwan.
Cheng Hai was stopped by security guards at the Hefei Xinqiao International Airport in the eastern province of Anhui on Tuesday, as he went through security.
"Cheng Hai may endanger national security after leaving the country," a security official says in a video of the incident filmed by Cheng.
"With the approval of the relevant department of the State Council, the Beijing Municipal Public Security Bureau is enforcing restrictions on your exit in accordance with the provisions of Article 12, Clause 5 of the Exit and Entry Administration Law of the People's Republic of China," the guard said.
In the video clip, Cheng argues with the guards.
"I tell you that you are committing a criminal act by preventing citizens from leaving the country, and abusing your power," Cheng said. "You behave like a criminal gang, even though you are wearing police uniforms."
Cheng had been hoping to fly from Hefei to Taipei, but declined to comment on the reason for the trip.
"I was going to Taiwan as a tourist, and with permission to participate in some business activities as well," Cheng said.
He said he plans to lodge a formal complaint.
"I will definitely be taking legal action, because their actions are criminal," he said. "According to Chinese law, any ban on citizens leaving the country must be decided by the relevant department of the State Council, but this was a decision made by the Hefei entry and exit checkpoint, who say they were told to do this by the Beijing police department."
Represented Falun Gong, lawyers
Cheng Hai has previously represented followers of the banned Falun Gong spiritual movement, which the ruling Chinese Communist Party has designated an "evil cult."
He has also acted as defense attorney to lawyer Wang Quanzhang. His ban comes amid an ongoing crackdown on hundreds of human rights lawyers and their families launched in July 2015.
The travel ban on Cheng comes after authorities in the Chinese capital enforced a travel ban on lawyer Chen Jianggang who was en route to the United States to take up a prestigious fellowship to study law and human rights earlier this month.
Chen Jiangang was prevented from boarding flight DL128 at Beijing's International Airport on Monday by border guards, who said they had instructions from the Beijing police department not to allow him to leave China.
Officials refused to give him any written explanation for the ban, but told him that his departure would "endanger national security," Chen said at the time
He told RFA on Thursday that he believes such decisions are made on the personal whim of officials, rather than having any legal logic behind them.
"I haven't done anything in the past couple of years; I didn't take any cases, nor did I write any open letters," Chen said. "I just prepared for my study leave, so why was I banned, when a lot of other lawyers affected by the July 2015 crackdown have been allowed to leave China?"
"I have to say that I don't know if there is any logic behind this, but my personal feeling is that it's totally down to the personal whim of certain individuals; there is nothing legal about it," he said.
Repeated calls to the Beijing municipal police department rang unanswered during office hours on Thursday.
Reported by Gao Feng for RFA's Mandarin Service. Translated and edited by Luisetta Mudie.