Amnesty International has called on the Chinese authorities to release a Beijing activist detained after posting a photograph of the 1989 Tiananmen Square demonstrations on the internet. Bai Dongping is being held on the charge of “incitement to subvert state power” after he posted the image on the popular online forum and chat service QQ. A prominent activist during the 1989 pro-democracy protests in Beijing, Bai Dongping is one of several Chinese activists to have been harassed and detained as part of an ongoing crackdown after the imprisoned author Liu Xiaobo was awarded the Nobel Peace Prize in October. “The authorities must release Bai Dongping who is being held simply for peacefully exercising his right to freedom of expression,” said Catherine Baber of Amnesty International. “They must also stop this campaign of intimidation and harassment of activists, in the run-up to the Nobel Peace Prize ceremony on 10 December.” Bai Dongping was arrested by the national security police at his home in the Xicheng district of Beijing at 1am on Saturday. The officers also took away his mobile phone and computer. Bai, a member of the Petitioners and Rights Defenders' Group of lawyers, was released at 5am only to be rearrested at mid-day. According to Bai's wife Yang Dan, he is now being held at Xicheng police station. Yang Dan said that the police verbally confirmed the charge as “incitement to subvert state power” and said that her husband would be held for 30 days. According to Yang Dan, during the brief time he was released, Bai Dongping said that the police had primarily questioned him about his work with the Petitioners and Rights Defenders' Group. In recent months almost every member of the group has been questioned by police. Liu Xiaobo is to be officially awarded the Nobel Peace Prize at a ceremony in Oslo on 10 December. The scholar and author, is currently serving an 11-year sentence on charges of “inciting subversion of state power” imposed after an unfair trial. The 54-year-old is a prominent government critic who has repeatedly called for human rights protections, political accountability and democratization in China. He participated in the demonstrations on Tiananmen Square in 1989 and has dedicated his Nobel Peace Prize to those who “all those who have sacrificed their lives in non-violent struggle for peace, democracy and freedom”. Bai Dongping was a prominent activist during the 1989 student-led pro-democracy movement in Beijing. Hundreds of civilians were killed and thousands injured 21 years ago during the violent military crackdown on peaceful demonstrators in and around Beijing's Tiananmen Square on 3 and 4 June 1989. Amnesty