The police arrested a mainland man at the West Kowloon Station on suspicion of being in possession of flares.
The incident happened at around 2:30 p.m. when authorities received reports of a 49-year-old man being found with five suspected flares when undergoing security checks at the station.
Police officers subsequently arrested the man on suspicion of making or possession of explosives. He remains detained and continues to be investigated.
No injuries related to the incident have been reported so far.