AN American tourist staying at the Grand Hyatt hotel was robbed at gunpoint early yesterday by a man police believe may have been posing as a room-service waiter. Howard Hamburger, 46, opened the door to his 27th-floor room at about 2.30am to be confronted by a pimply-faced young man who threatened him with a pistol and forced his way in. Mr Hamburger was ordered to open the safe and hand over US$7,500 (HK$58,500) and to give the robber the watch and gold necklace he was wearing. Police said the guest opened the door because he thought the man was a member of the hotel's staff. Mr Hamburger described the robber as having short hair and an Asian appearance, but with blue eyes. The offender was about 170cm tall and wore black trousers. 'This is extremely unusual in Hong Kong, and this the Grand Hyatt - it's a hotel with such tight security,' James Lu Shien-hwai, executive director of the Hong Kong Hotels' Association, said last night. The Grand Hyatt is one of Hong Kong's most exclusive hotels. US President Bill Clinton stayed there during his 1998 visit to the SAR. A basic room costs between $3,200 and $3,500 a night, depending on the view. Hotel duty manager Vivian Chan Ngar-wai said the incident was 'definitely not' a regular occurrence, but would not say whether security had been stepped up after the robbery. Wan Chai police are investigating the incident, but had not made any arrests by last night.