Hundreds of protesters rallied outside Peking University yesterday and on Monday in response to a leading professor's claims that petitioners were generally mentally ill, activists reported. Nearly 300 people, including about 200 city residents and 100 from outside Beijing, gathered in front of the university gates and held up signs for about three hours in the morning, one activist said. 'We just stayed there because the security guards did not let us in,' she said. Repeated calls to a university spokesman went unanswered. Protests near the university have been rare following the Tiananmen Square crackdown on pro-democracy students in 1989. Peking University professor Sun Dongdong, a psychiatrist and consultant to the Ministry of Health, was quoted as saying in an interview last month that 99 per cent of the mainland's 'professional' petitioners were paranoid and mentally disturbed. He was also quoted as saying that petitioners must be forcibly sent to mental hospitals otherwise they would disrupt social order. 'In order to keep those people from hurting themselves and society, the best way to protect their human rights is to send them to mental hospitals for compulsory treatment,' he was quoted as saying in the March 23 Chinese edition of Newsweek magazine. The remarks drew widespread criticism from petitioners, psychiatric patients and lawyers, who described them as shocking and irresponsible. Another petitioner said yesterday: 'We were so angry with the professor's comments. He seems like a fake professor. How could he attack common people and even weak people who just want to protect their own rights? We want him to apologise and explain his words.' He said they also went to the university to seek an apology on Monday and on Wednesday last week. The professor issued an open apology yesterday, saying that he regretted his comments. 'I'm deeply sorry for those improper expressions that sparked controversy and misunderstanding ... I extend my sincere apology to people whose feelings were hurt,' he said in a statement carried by China News Service. 'I have absolutely no prejudice against those petitioners ... I will make serious self-reflection and be cautious with my words and behaviour in future.' But one of the activists said the apology was insufficient. 'Some of us are seeking to file a lawsuit against him. We might continue with our petitions [in front of the university].' Liu Xiaoyuan, a Beijing-based human rights lawyer and blogger, said it was rare for a prominent university professor to make such an apology, but it still lacked sincerity. 'I think he did that because he was under huge public pressure from both internet users and experts,' Mr Liu said.