Chinese police seize 'warm-hearted' Tiananmen activist

Chinese activists are demanding the release of a veteran campaigner who was detained last week after years speaking out on issues including pollution, human rights abuses and Beijing's treatment of the families of those killed in the Tiananmen Square crackdown.

Chen Yunfei, a 47-year-old witness to the 1989 massacre in Beijing, has not been seen since March 25 when he was taken into police custody near the city of Chengdu.

He was detained shortly after visiting the grave of Wu Guofeng, a student who was gunned down during the 1989 massacre, with a group of activists and relatives.

"They stopped our car and asked who was Chen Yunfei," said Luo Kaiwen, a 77-year-old activist who was part of the group and said its members had been separated and, he believed, taken to different police stations.

"Nobody knows where they took [him]," Mr Luo added. "I called Chen's mobile phone repeatedly after I was released that night. But either no one was answering or it was switched off." Mr Chen appears to be the latest victim of a Communist Party offensive against dissent that has been gaining pace since Xi Jinping, described by some as China's most authoritarian leader since Chairman Mao, took power in November 2012.

His detention follows those of five feminist campaigners who were seized by police on the eve of International Women's Day on March 8 after planning a protest against sexual harassment.

Beijing accused the United States and Britain of "interfering in China's judicial sovereignty" after they called for the women to be released.

On Thursday, one week after Mr Chen's detention, Ran Tong, his lawyer, said he still had no information on where his client was being held. Mr Chen's family had reported the activist missing to police, he added.

"There is very little I can do right now apart from to give advice to relatives and to call on the public to pay attention to this case which is very strange," Mr Ran said.

Mr Chen was "a warm-hearted citizen" who believed his duty was to "supervise" those in power, the lawyer said.

He regularly campaigns on human rights and environmental issues and spent six months under house arrest in 2007 after taking out an advertisment in a Chinese newspaper paying tribute to the victims of the Tiananmen crackdown on June 4, 1989.

"Both the students and the soldiers who died were sacrified by the system," Mr Chen, who was a student in Beijing at the time, told the BBC in 2009.

"Would a democratic country use tanks and real bullets against its own people? I don't think so."

In March this year, Mr Chen was reportedly "dragged" away from a protest outside a petrochemical plant in Sichuan province.

Friends have long feared that Mr Chen would suffer retaliation from authorities who consider him a nuisance. His detention was likely an act of "revenge," Mr Ran said.

Additional reporting Ailin Tang