The leader of the banned Hong Kong National Party, Chan Ho-tin, says he has been detained at the airport while preparing to board a flight.

Writing on FaceBook, he said he only knew that the detention was requested by the local police, but the reason was unknown.

The police have not responded to the incident for the time being.

Chan was among eight people arrested for possession of offensive weapons following a raid in Sha Tin earlier this month.

Officers swooped on the Haribest Industrial Building on Au Pui Wan Street, where they claimed they found materials for making petrol bombs and other weapons.