Pro-democracy campaigners fired used petrol bombs, arrows and even catapults against police as the battle for power in Hong Kong moved to a university campus in the Chinese territory’s central Kowloon district.
Police responded with tear gas and pepper spray.
The Hong Kong Polytechnic is the last of five universities to be in the hands of the activists and it is used as a base from which to block the Cross-Harbour tunnel.
Tensions have been heightened by reports of Chinese soldiers making a rare public appearance on the streets of Hong Kong.
Dozens of Chinese troops, dressed in black shorts and olive drab T-shirts, ran out in loose formation and picked up paving stones, rocks and other obstacles that had cluttered the street.
The military is allowed to help maintain public order, but only at the request of the Hong Kong government. The government said that it had not requested the military’s assistance, describing it as a voluntary community activity.
Months of protest in the former British colony have seen campaigners clash with the authorities over allegations that Beijing is attempting to reduce its autonomy.
Protesters have tried to turn the university campuses into armed camps, resorting to medieval-style weapons such as bows and arrows, catapults and gasoline bombs to stop police from entering the grounds.
Protesters said they need the weapons to protect the campuses from police using tear gas
A Hong Kong police officer was hit in the leg by an arrow on Sunday. Police said the weapon struck a media liaison officer, who was taken to a hospital. Photos on the department’s Facebook page show the arrow sticking out of the back of the officer’s lower leg.
Education officials announced that classes from nursery to secondary school would be suspended again on Monday because of safety concerns.