After weeks of violent unrest, Hong Kong once again witnessed the rounds of protests on Tuesday when anti-government demonstrators fought intense battles with riot police on a university campus and paralysed the city’s upmarket business district.

The flare-ups occurred a day after police shot an unarmed protester at close range and a man was doused with petrol and set on fire in some of the worst violence since the protests began nearly five months ago in the China-ruled city.

Earlier on Tuesday, the city’s universities emerged as a new flashpoint with sustained clashes at major campuses for the first time.

Hundreds of masked protesters, many of them students, hurled back petrol bombs, rocks and bricks, some launched with catapults. After the clashes, dozens of the injured lay sprawled on the ground at a nearby sports pitch.

Protesters also responded with bricks and petrol bombs, while a vehicle used in a barricade was set alight.

After a brief hiatus in which faculty staff tried to mediate, new clashes broke in the evening with flames lighting up the night sky and fresh rounds of tear gas whizzing through the air.

Police used a water cannon truck in an attempt to dislodge protesters but they remained behind their makeshift shield walls.

There were smaller clashes on at least three other university campuses throughout the day.

On Sunday, a 21-year-old who was shot by a policeman and a 57-year-old man who was set on fire after an argument with protesters remained hospitalized in “critical condition”.

According to local media reports, some public transport services were again disrupted during rush hour on Tuesday morning, and clashes between riot police and protesters were resumed on some university campuses, where officers used tear gas.

Hong Kong has been upended by five months of huge and increasingly violent rallies, but Beijing has refused to give in to most of the movement’s demands.

Tensions have soared in recent days following the death on Friday of a 22-year-old student Alex Chow, who succumbed to serious injuries sustained from a fall in the vicinity of a violent clash the weekend before.

The protests, which have been drawing massive crowds since June following a contentious proposed extradition law that has been pulled by the government, have mutated into a movement that seeks to improve the democratic mechanisms that govern Hong Kong and safeguard – or expand – the region’s partial autonomy from Beijing.

The controversial China extradition bill was withdrawn in early September but the movement has morphed into a wider campaign for greater democracy and against alleged police brutality.