Four mainland legal experts have denounced internet portal Sina.com for deleting weblog articles they wrote which contain 'sensitive words', and appealed for awareness about infringement of freedom of speech. Peking University professor He Weifang, China University of Political Science and Law professor Xiao Han, and Beijing lawyers Pu Zhiqiang and Xu Zhiyong signed a declaration titled 'Sina, please publicise your reason', which quickly circulated on the internet overnight. The four, who each have blogs on Sina.com, complained that many of their posts were deleted without notice. They claim their freedom of speech was infringed and are considering a lawsuit against Sina, a portal that has gained great popularity through its celebrity blog service over the past two years. In the statement, the four said: 'There have been many articles deleted by Sina administrators. 'But recently some articles containing names such as Zhang Yihe [a banned writer who started a public protest against the authorities] and Cui Yingjie [a vendor whose killing of an inspector and subsequent death penalty sparked debate about urban inspectors] were deleted, including long comments by visitors.' They asked Sina to explain which administrative departments or laws authorised the deletion. Yesterday, a Sina.com customer service employee said the portal had a team of monitors supervising blog articles at all times. Under its criteria, 'articles and messages that go against national laws, contain sensitive words and issues listed by government departments, and pornographic articles will be deleted'. But the employee refused to say what constituted 'sensitive words and issues', saying 'they were all decided by governmental administrations and should not be publicised'. Professor Xiao said Sina's censorship was tougher than the print media's. His request for an explanation from Sina has been ignored. 'This is such a common and rampant practice that people all tolerate with acquiescence. It becomes a behavioural code on the internet,' said Professor Xiao. Professor He said censorship on the internet had become crazy and the declaration was just a way to 'raise people's awareness of this issue and urge internet administrators to realise their social responsibilities'.