HONG KONG - A Hong Kong court sentenced a separatism advocate to 12 years in prison on Friday for possessing over 1 kilogram of explosives — part of the largest seizure in the city in nearly a quarter-century — during the social unrest of 2019.

The sentence is to date the heaviest handed down on charges relating to the 2019 social unrest.

Lo Yat-sun, 29, is a former member of a local radical separatist group, the "Hong Kong National Front", which was disbanded in Hong Kong in June. He pleaded guilty in early April to one count of keeping explosive with intent to endanger life or property.

High Court Judge Andrew Chan Hing-wai, who presided over the case, said a deterrent sentence was a must, given that evidence showed that Lo had intended to create fear and terror among the public and overthrow the government of the special administrative region.

Lo was arrested in July 2019, with three others after police found the explosive material triacetone triperoxide (TATP), 10 homemade gasoline bombs, and other protest-related devices in a unit of an industrial building in Tsuen Wan, Western New Territories. A large number of books, banners, and leaflets touting separatism were found in the unit and in Lo's apartment.

Chan said the case was even more serious than a notorious 1997 case in which gangster Yip Kai-foon was imprisoned for 18 years for possessing 2 kg of explosives.

The separatist group's explosives were detonated on the building's rooftop after showing instability and threatening destruction. The whole building and the surrounding streets had to be cordoned off.