Groups of black clad students huddled in an outside courtyard mixing liquids and detergents. Peggy sits on a bridge at Polytechnic University surrounded by crude weapons. Credit:Kirsty Needham Another group busied themselves in the canteen pouring beer into large plastic tubs to be wheeled to the toilets and flushed away - it was the glass bottle that was instead prized by students tonight. More students constructed a catapult using desk parts and a helmet. Fumes wafted in the air. Peggy, 21, a final year student, said: "I came to the campus six hours ago because this morning police fired tear gas. Two days before, they occupied this bridge and fired rubber bullets. So I came to support my class mates."

While Hong Kong police accuse university students of taking a step closer to terrorism with their bomb making, the students argue the reason for making petrol bombs is to defend themselves against police. Polytechnic students built new brick walls to barricade the campus on Thursday night. Credit:Kirsty Needham A dramatic clash on Tuesday night saw over a thousand flaming tear gas canisters and rubber bullets fired by police on a bridge at Chinese University. More than 60 students were injured. Standing across the road from the Polytechnic campus, and below a People's Liberation Army barracks where Chinese soldiers hissed warnings if anyone came too close to the front gate. An Australian family watched the student fortifications build up.

Protesters practice throwing molotov cocktails into a swimming pool at Hong Kong Polytechnic University. Credit:AP Barbara, who moved with her husband from Perth 17 years ago, said: "I think that it is widely accepted by the community, especially by those who don't have the confidence to get in there and fight." "It is actually showing how united Hong Kong is," she said, gesturing to the scores of onlookers. The family don't want their surname published because of the risk to careers in Hong Kong as companies, under pressure from Beijing, crack down on public support for the protesters. Hong Kong students building a catapult. Credit:Kirsty Needham

"It directly affects us, we live here, we can't get the children to school, the school gets cancelled. But I feel that they have to fight for their democratic rights. I'm not so ok with the violence, but they have to stand," says Barbara. Chinese cameras were installed earlier that day on the military barracks fence, and are pointing at the university. Thousands of black clad protesters poured into the Polytechnic University, passing through a series of "security checks" where bags were searched, to prevent undercover police infiltrating the campus. Inside Polytechnic University supplies are piled on tables like a protester supermarket. Credit:Kirsty Needham New brick walls were rapidly cemented into place to block any police charge down internal campus lanes.

Michelle, 22, sat on a mat in the campus gym with two friends. They had been there for two days. Loading "The soldiers may come, that is what we fear," she says. She is surprised at how well organised the students inside the campus have been - providing hot meals and even clothes. "There is a lot of love. We came to defend our home."

In the canteen, a pop-up protester supermarket had emerged. Tables are piled high and aisles labelled for easy shopping: Goggles, masks, towels, clothes, detergent (for washing off pepper spray), salt (for washing eyes), construction tools and instant noodles. Assistant professor of applied social sciences, Dr Kaxton Siu, was manning a stall in the courtyard seeking graduates to join a team offering counselling to protesters. Loading Replay Replay video Play video Play video The windows behind him are smashed, with the words "Liberty or Death" painted above.

The students had learnt rapidly from other university campuses in the past 24 hours, he said. "Last night they built basic barricades but today they are building walls." While there were so many people on campus, it would be relatively safe from police attack, he said. "The most dangerous time is between midnight and 3am, because the harbour tunnel has been blocked and the police need to reopen the tunnel so people can go to work." In London, Hong Kong's Justice Secretary Teresa Cheng was targeted by protesters during a visit to the UK to promote the territory's interests. Video footage of the incident showed Cheng falling to the ground, but it was not clear whether the fall was accidental. Hong Kong Chief Executive Carrie Lam condemned the protesters.