The dismissal of a well-known liberal scholar from a government institute is being viewed as a sign that controls over intellectuals are being tightened ahead of the 20th anniversary of the Tiananmen Square crackdown. Liu Junning, 48, a researcher on social issues at the Institute of Chinese Culture under the Ministry of Culture, confirmed yesterday that he had recently received official notice of dismissal. 'I am sorry that I cannot say too much right now. Thank you for your understanding,' he said. It was the second time in nine years that he had been expelled from an official research institute. He was kicked out of the Chinese Academy of Social Sciences' (CASS) Institute of Political Science for introducing liberal ideas. Intellectual Xu Youyu and playwright Sha Yexin said yesterday they had heard rumours that they and Professor Liu had recently been criticised in name by a member of the Politburo Standing Committee for their liberal views. Dr Xu, who used to work for CASS' Institute of Philosophy and retired two years ago, said neither of them could confirm the rumour, and they had not received any notice of punishment so far. 'Therefore now is not the right time to comment on the issue,' he said, adding that he believed retired people were not immune from punishment. Mr Sha, 69, a retired Shanghai-based playwright, said the punishment of liberal intellectuals on the mainland was nothing new. He said intellectuals had found themselves in the firing line soon after the Communist Party took power. From the early 1950s to late 1970s, millions of outspoken intellectuals were thrown into labour camps or jail. Late party chief secretary Hu Yaobang, whose death triggered the student movement in 1989, had told the party that it would not be allowed to punish intellectuals based only on their words. 'I believe Hu's speech represents the majority of the party,' Mr Sha said. It is not clear what triggered the moves against Professor Liu. Bei Feng, an influential political blogger, said it was a warning to all liberal intellectuals ahead of the 20th anniversary of the June 4 crackdown. The blogger said the three were connected, and last year had signed the pro-democracy manifesto Charter 08, which called for constitutional reform and an end to one-party rule, and was regarded by Beijing as a sign of anti-government activity.