Hong Kong police said on Thursday night that they seized 3,801 petrol bombs, 921 gas canisters and 588 chemicals, including acid and other corrosive liquids during their search of Hong Kong Polytechnic University (PolyU), which was recently a locus for protest activity. On November 17, rioters took the campus as a stronghold to launch assaults on police officers, using lethal weapons, including petrol bombs, bows and arrows, metal balls and bricks. The Hong Kong police are holding a press conference with more details.