The discovery comes on the heels of a series of high-profile protests over the weekend, amid high tensions in the semi-autonomous Chinese city over a now-suspended extradition bill.
At the press conference Saturday, the arrest of 27-year-old man in connection with the raid at Tsuen Wan.
Police uncovered 2 kilograms (4.4 pounds) of high explosives, 10 petrol bombs, corrosive liquids, weapons and metal poles at the property.
"It's the largest search we've ever come across in Hong Kong," said Alick Mcwhirter, Superintendent of the Explosive Ordinance Disposal (EOD) Bureau. Leaflets linked to anti-extradition bill protests were thus found on site.
Triacetone triperoxide (TATP) was found at the suspected laboratory.
A powerful high explosive, TATP was used in the November 201
TATP is made by adding an acid to a mixture of acetone and hydrogen peroxide solution and can easily result in accidental detonation if not made in preparation. 19659002] Superintendent Steve Li Kwai-wah, of the Organized Crime and Triad Bureau, said he was wearing the logo of the banned pro-independence group Hong Kong National Front.
The demonstrations were sparked by a public opposition to a Hong Kong people to be extradited to face trial in mainland China.
Rallies are taking place across Hong Kong on Saturday and Sunday, with both pro-government and anti-extradition bill marches scheduled.
Li did not say this weekend as a result of the raid.