CORRECTIONAL Services Department (CSD) officers have been urged to avoid unnecessary risks in an operation today to remove another 1,500 Vietnamese from the vast Whitehead detention centre. Violent clashes are expected and Governor Chris Patten has already expressed sympathy and support for the force assigned to the operation. He also asked to be kept informed from early morning when 200 CSD emergency squad officers and about 1,000 police are due to converge at the camp. Section 1 is being cleared as part of an ongoing camp closure operation which saw Section 7 cleared last year and Section 8 emptied last month. Several Vietnamese who attempted to take up an offer to leave the compound yesterday were blocked by hardline members of the camp. By last night only 197 had moved out. The CSD Officers' Association said it had been refused permission to have its own monitors join a team of independent observers and United Nations High Commissioner for Refugees officials. Association spokesman Yum Pui said members had been advised not to hesitate in pursuing assault charges against any Vietnamese who attacked or injured them. He said the association had told officers not to risk their lives or take action which involved an unnecessary risk. Today's operation will be the first large-scale operation at Whitehead since April 7 last year when about 1,250 police and CSD officers were ordered to fire more than 500 tear-gas canisters to remove people from Section 7. Many Vietnamese were burned by the igniting canisters and almost 200 sought medical treatment. An independent inquiry found that excessive violence had been used by some CSD officers against some Vietnamese. An announcement of an imminent transfer was made at the camp in Section 1 on May 12. But in a departure from recent practice, the Government left it until about midday yesterday to tell the 1,500 people that they would be removed and taken to High Island detention centre today if they did not leave voluntarily either for transfer to High Island or to a departure centre. Last time, detainees had been given several days notice of the deadline and they all left voluntarily. Yesterday's warning prompted 1,200 people to march through the compound in protest. However, officers at the camp and Security Branch policy makers believe the group in Section 1 is far more militant. They claim the advance notice will have allowed the Vietnamese to make plans to challenge their removal.