Pro-democracy protesters paralysed parts of Hong Kong for a fourth day on Thursday, forcing schools to close and blocking highways, as students built campus barricades and stockpiled weapons and the government dismissed rumours of a curfew.

Thousands of students hunkered down on several campuses, surrounded by piles of food, bricks, petrol bombs, arrows with heads wrapped in cladding, catapults and other homemade weapons.

Police said the Chinese University, in the New Territories, had become a “weapons factory and an arsenal” with bows and arrows and catapults.

“Their acts are another step closer to terrorism,” Chief Superintendent (Public Relations) Tse Chun-chung told a briefing, referring to protests on all campuses.

He also said police would temporarily avoid directly clashing with “high-spirited rioters” to give themselves a breather and avoid injuries.

China’s Global Times tabloid, owned by the state-run People’s Daily, the mouthpiece of the Communist Party, said on Twitter that the Hong Kong government was expected to announce a weekend curfew after some of the worst violence in decades in the Chinese-ruled city.

It deleted the post after a short time. The Hong Kong government said the rumours were “totally unfounded”.

Protesters have torched vehicles and buildings, hurled petrol bombs at police stations and trains, dropped debris from bridges on to traffic below and vandalised shopping malls, raising questions about how and when more than five months of unrest can be brought to an end.

Police said arrows were fired at officers from Hong Kong Polytechnic University in the morning.

Several universities announced there would be no classes on campuses for the rest of the year.

Baptist University, next to a People’s Liberation Army base in Kowloon Tong, issued an “urgent appeal”, telling students to stay away from campus.

“Your safety is so dear to our hearts and to your parents' and friends’ hearts,” it said. “Please stay away from harm’s way.”

Hundreds of protesters occupied roads in the city’s business district, home to some of the world’s most expensive real estate, in the middle of the day.

Across the harbour, black-clad protesters and students maintained their blockades of major roads, including the entrance to the Cross-Harbour Tunnel that links Hong Kong island to the Kowloon area, and a highway between Kowloon and the rural New Territories.

Police fired tear gas near the tunnel early on Thursday to try to clear the protesters. Roads were strewn with bricks and other debris, causing widespread traffic jams.

At the Polytechnic University, near the Kowloon entrance of the Cross Harbour tunnel, hundreds of students wearing gas masks readied for confrontation. They were practising throwing petrol bombs and archery in a half-empty swimming pool.

Boxes of petrol bombs were placed at vantage points overlooking roads, including the tunnel, which has been blocked since Wednesday evening. Violence has escalated in recent days, with police shooting and wounding one protester at close range.