Nine men aged between 20 and 25 were arrested by Hong Kong’s National Security Department in the force’s first use of the “unlawful drilling” charges after officers raided a heavily secured San Po Kong industrial unit used for military-style training and found an arsenal of weapons and homemade explosives.

The operation began yesterday evening when officers armed with a court warrant stormed the locked unit, where six men were present and one was giving instructions.

A search uncovered five long air rifles, two air pistols, five replica daggers, one replica sword, combat gear, slogans linked to the 2019 protests, a 3D printer, and modified explosive devices fitted with fuses. 

Three more suspects were later arrested in Tuen Mun and Yau Ma Tei.

All nine detainees, who described themselves as clerks, security guards, and restaurant workers, face charges of unlawful drilling. 

Chief Superintendent of police for National Security Steve Li Kwai-wah said the structured training involved offensive weapons and formation drills and expressed concern that some suspects had voiced intentions to use the skills against police and government officials if large-scale unrest returned. 

He stressed that even low-grade explosives can cause serious injury and noted that some of the men had appeared in protest-related clothing at a recent fire scene in Tai Po, raising fears of a revival of 2019-style violence.

Investigations continue into the manufacture, purpose and wider network behind the weapons and training activities.