Police detained at least six of Xu Wenli's colleagues to prevent supporters rallying outside Beijing's No 1 Intermediate People's Court when he was tried yesterday. The dissidents were warned there might be a possible second-wave crackdown on political activism. During the trial, uniformed and plain-clothes police cordoned off the court, preventing journalists and other bystanders from approaching within 500 metres of the building. Gao Hongming, vice-chairman of the Beijing-Tianjing branch of the banned opposition China Democracy Party, said: 'I was taken away by three public security officials when I left my house for the court at 7.05am. I was kept under watch by them at the Hot Spring Hotel in the Chao Yang district until 1.30pm. 'The public security officers asked me if I was afraid of being jailed for engaging in anti-government activities. They then asked me to take a sauna to soothe my flu.' Another vice-chairman of the branch, Zha Jianguo, was taken by officers on Sunday to Huairou county, where he was kept at an official training centre until 4pm yesterday. Other Beijing-based members of the party, including He Depu, Wang Zhixin, Xu Yonghai and Yan Zhengxue, were also temporary detained during the trial. The China Democracy Party strongly protested over the 'illegal act' of authorities in sentencing Xu to 13 years in jail and imprisoning Wang Youcai for 11 years. 'We demand the unconditional release of Xu and Wang,' the party said. Mr Zha said it was irrational to pass such heavy penalties on dissidents who were using non-violent ways to seek change. 'Such treatment shows that the Communist Party is really ailing,' he said. Mr Gao said: 'The United Nations, foreign governments and international human rights organisations should jointly put pressure on the Chinese Government to avert the harsh treatment of dissidents. 'It is obvious such harsh sentences are aimed at scaring away supporters or sympathisers of the party. 'Our development may slow down because of such oppression. 'But we can assure Beijing leaders that it would be impossible to arrest or jail all our members.'