Hong Kong Police will investigate the deaths of the Hong Kong tourists slain in Monday's hostage tragedy in Manila, and will exchange information with the Philippine authorities through Interpol when necessary, Under Secretary for Security Lai Tung-kwok of Hong Kong said Saturday.

Speaking on radio talk shows, Lai said although Police officers cannot take enforcement action in Manila, they can ask to collect evidence from witnesses in the presence of their Philippine counterparts.

Hong Kong has sent two Police officers to Manila to assist in the investigation, and their work has gone smoothly. More officers will be sent to the city if necessary, he added.

Survivors' statements will be essential to the investigation, Lai said, adding arrangements will be made when they are in a fit state.

The government will also arrange sharing sessions for all staff who went to Manila to help the victims. The move will help alleviate emotional problems arising from the incident, he said.

An ex-policeman turned gunman hijacked a tour bus carrying 21 Hong Kong tourists Monday morning in Manila, the Philippines. The incident ended with eight tourists dead and seven injured. The hostage taker was killed in police assault.