Hong Kong police have defused a homemade pipe bomb and found equipment suspected of being used to make explosives at residential units in Mong Kok and Sheung Shui. Four men have been arrested in connection with the case.

The men, aged 21 to 29, were arrested on Tuesday on suspicion of unlawful assembly, possession of explosives, conspiracy to manufacture explosives and possession of drugs. Three of them were students, RTHK reported.

A suspected homemade metal pipe bomb. Photo: RTHK screenshot.

New Territories North Regional Crime Headquarters Senior Superintendent Chan Tin-chu said police had found a homemade metal pipe bomb at a residential building on Tung Choi Street in Mong Kok. They also found equipment suspected of being used to make explosives at a house at the Ho Par Village in Sheung Shui.

Chan said police believed the arrestees were core members of a “relatively hidden valiant group.” The term “valiant” has often used to describe frontline guerilla protesters. The group was suspected of participating in an unlawful assembly in Mong Kok on January 1, when crowds of protesters set barricades alight and volleys of tear gas were fired in response.

Chan Tin-chu. Photo: RTHK screenshot.

“According to our intelligence, we believe they were planning to attack police officers or police facilities,” he told reporters.

Chan said that a small explosion occurred when police defused the bomb at the Mong Kok unit, blowing a hole in the door of an elevator.

Photo: RTHK screenshot.

“If it was thrown into a car like a grenade, I believe… people inside would certainly have died,” he said.

Asked why police did not evacuate residents inside the building, which contained many subdivided flats, Chan said police at the Explosive Ordnance Disposal Bureau decided not to do so after conducting a safety evaluation.