HONG KONG, Nov. 28 (Xinhua) -- The Hong Kong police said on Thursday night that they have seized 3,801 petrol bombs and many other dangerous items and offensive weapons inside the Hong Kong Polytechnic University (PolyU).

At a media briefing about the operation of the safety team deployed into the PolyU on Thursday, Assistant Commissioner of Police (Operations) Chow Yat-ming said that officers of the police and fire services department were split up into different groups and systematically entered into different buildings inside the campus to remove and handle all the dangerous items and offensive weapons, as well as to gather evidence at the scene of crime.

After more than 10 days of occupation by radicals, the campus has been badly and extensively damaged, with a large number of petrol bombs, gas cylinders and corrosives exposed under the sun light for a long time, which posed a serious threat to all personnel at the scene, Chow said.

According to Senior Superintendent Li Kwai-wah of Organized Crime and Triad Bureau of the police, in Thursday's operation, the team seized 3,801 petrol bombs, including 100 tied with cassette gas bottles to make greater damage.

They also seized 921 cassette gas cylinders, 558 bottles of different kinds of chemicals, including strong acid, strong alkali, corrosive liquids and chemicals that can be used to make explosives.

As for offensive weapons, the police seized a number of bows, about 200 arrows, one air rifle and four boxes of nails that were extensively used in the vicinity of the PolyU.

In the car park of the university, the police found that fuel tanks of 44 vehicles were damaged by rioters to steal petrol and make petrol bombs, and several other vehicles were maliciously vandalized.

Deputy Chief Fire Officer (Licensing & Certification) Wong Chun-yip said that as of 9 p.m. officers of the fire services department have inspected the podium, laboratories, all the dangerous goods stores and most buildings on the campus.

During the inspections, they found a large quantity of dangerous chemicals, including a large amount of petrol bombs, LPG hydrogen, over 550 liters of flammable liquid, 20 liters of corrosive fluid, and 80 liters of toxic substances.

They also found that the laboratories of the university have been broken in and vandalized and a total of 15 fire extinguishers outside the dangerous bookstores have been missing.

The operation will resume on Friday morning as there are still some work needed to be done by the police and fire services officers during the daytime, Chow said, adding that the team are expected to finish their tasks on Friday.

"I'm confident that we can finish it by tomorrow and return a safe campus to the university management," he said.