A burst of violence in Hong Kong has pushed the city, gripped by more than five months of political unrest, even further away from the possibility of peaceful resolution.

After the death of a demonstrator on Friday and a weekend of clashes between police and protesters, Hong Kong woke up on Monday to live footage of a police officer shooting a 21-year-old student at close range in the stomach. Later, videos emerged of a 57-year-old construction worker being set on fire while arguing with demonstrators, and a police officer repeatedly driving his motorbike at a group of protesters.

Those scenes, already some of the most graphic examples of violence since the anti-government protests began, were soon eclipsed by an hours-long battle at one of Hong Kong’s most prestigious universities. Police rained teargas and rubber bullets on students, shrouding the school in smoke as protesters responded with molotov cocktails and in some cases fiery arrows dipped in petrol.

On Wednesday, as parts of the city were paralysed, protesters at universities were bracing for more confrontations, stockpiling petrol bombs, bamboo poles and other weapons. Some were armed with javelins, bows and arrows.

“It has been an escalation of violence because of an accumulation of several cases … the hostilities were escalating on both sides,” said Ma Ngok, a political scientist at the Chinese University of Hong Kong, the site of protests on Tuesday night.

Play Video 0:49 Hong Kong protesters shoot arrows at police during clashes at Chinese University – video

The last week has been among among the worst Hong Kong has seen after months of protests comprising peaceful rallies as well as street brawls and pitched battles between riot police and young protesters. More than 400 people were arrested on Monday and Tuesday, according the police.

Experts say the Hong Kong government, under the chief executive, Carrie Lam, has been taking a harder line on protests after a meeting with the Chinese president, Xi Jinping, earlier this month in Shanghai where he called for “unswerving efforts” to punish violent activities.

On Monday, Lam labelled the protesters “enemies of the people”, while the police blamed the demonstrators for pushing the city “to the brink of collapse” and described them as criminals.

The government has relented on one of the protesters’ five demands, the formal withdrawal of an extradition bill that would allow suspects to be sent to mainland China. Lam has refused to meet the other demands, which include an independent investigation into the police force for alleged police brutality over the last five months.

“She has since toughened up, giving unconditional backings to the increasingly aggressive and disproportionate use of force,” said Kenneth Chan, a professor at Hong Kong Baptist University and former lawmaker.

“She has no political solution and is no longer mentioning her ‘dialogues with the people’,” he said, adding that antagonism between the police and protesters, who the police call “cockroaches” had reached a new level. “It is undeniable the police and the young protesters hate each other,” he said.

Observers have noted that the emergence of universities as battlegrounds represents a major escalation for the protesters, many of whom are students and alumni. Over the course of the protests, the police have not entered school campuses.

“The university is the home turf of the students,” said Ho-Fung Hung, a professor in political economy at Johns Hopkins University. “There is this notion of academic freedom and the university as a bastion of free ideas, this notion of autonomy. To people, this should not be breached by authorities.”

The rise in unrest comes as Hong Kong prepares to go to the polls for district council elections on 24 November. In recent weeks, a pro-government lawmaker has been stabbed and a pro-democracy district councillor had part of his ear bitten off, raising questions about whether the elections should go forward.

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Some have accused the government of encouraging more confrontations as a pretext for postponing the elections, where opposition candidates are expected to make major gains. Cancelling the elections would only make the situation worse, observers say.

“It is very volatile and difficult to predict. These two weeks in the run-up to the election … will have a determining effect. If the government cancels the elections, things will escalate more. It will look like the last institutional channel for people to express their opinion and anger through voting is shut off,” said Hung.

In recent days, the police have made efforts to dissuade members of the public from supporting the “rioters” and described anyone who excuses their violence as “accomplices”.

Yet even as some protesters have grown increasingly radical in the past few months, vandalising public transit stations, trashing businesses seen as pro-government, or beating people believed to be spies, they have retained public support.

On Wednesday, volunteers were bringing supplies to protesters at universities, which were expected to turn into flashpoints. Following the shooting on Monday, office workers and bystanders in Hong Kong’s central business district have joined daily lunchtime demonstrations, deemed unlawful by police, who have used teargas against the crowd on all three days.

isabella steger (@stegersaurus) still in shock at how many people are rallying for Poly U. another car queue forms round the side of the school...opposite the PLA barracks pic.twitter.com/SwtR4ErFMx

“Public opinion seems to not be affected by this protester militancy. They still blame the police more for the escalation,” said Hung.

For now, tensions have reached such a level that it is unclear meeting other key demands of the protesters would help calm the situation. “Setting up the investigation might not help but continuing to be against it gives the impression the government is not serious or doesn’t have the intention to de-escalate,” he said.

The crisis could deteriorate even more, warned Hung. “It is not yet an order or policy to use live bullets. The next step of deterioration is they decide not to use rubber bullets but to use live bullets.”