Hong Kong police have arrested 120 people, including 14 minors, and seized worth HK$26 million (US$3.31 million) in a month-long operation targeting multiple online sales of illegal narcotics and related products.

Chan Lik-ho, a senior inspector with the force’s narcotics bureau, said on Monday that 53.7kg (118lbs) of dangerous drugs and Part 1 poisons were seized during an operation codenamed Amberflock, carried out from March 29 to April 25.

He said there were 74 cases involving 78 male and 42...