A 14-week anti-terrorist exercise involving 3,900 security and other government officers ended yesterday. The drill was designed to raise the awareness and improve the readiness of all frontline officers. Police said the exercise went smoothly and a full assessment of the drill would be conducted. Chief Inspector Joseph Tung Wai-cheung said the risk of a terrorist attack in Hong Kong remained moderate. 'There is no intelligence to suggest that Hong Kong is a target for terrorist attacks,' he said. 'But we have a responsibility to prepare ourselves so that if something happens, we would be capable of handling such an incident effectively.' The exercise, codenamed 'Spellbinder', was conducted in four phases with a series of simulated terrorist incidents. Most of the 3,900 participants were not told in advance how the 'terror attacks' would unfold. They included officers from the police, fire services, Hospital Authority, Health Department and Security Bureau. Phase one to three of the exercise took place between July 20 and September 30 and simulated threats of various kinds, including bombing attempts at a public pier, a police station and shopping mall. Mock investigations by the Organised Crime and Triad Bureau found the incidents were perpetrated by a terrorist group. A raid on a terrorist hideout resulted in four suspects being 'shot dead' in a gunfight, while three terrorists remained at large. The concluding episode of the drill, staged yesterday, saw the three terrorists detonate an explosive device that released sarin gas at the forecourt of Sha Tin Racecourse during a private auction attended by about 150 overseas guests and celebrities. About 1,300 officers from the police and other government departments responded to the incident by setting up decontamination facilities to provide emergency treatment at the scene before ferrying the 'casualties' to the Alice Ho Miu Ling Nethersole Hospital. The scenario concluded with two of the wanted terrorists killed in the explosion, while the remaining one was arrested at Tai Wai train station.