Hong Kong police have fired rubber bullets and tear gas in a bid to hold back anti-government protesters fleeing a university where hundreds were holed up with petrol bombs and other homemade weapons, amid fears of a bloody crackdown.
Dozens, reportedly choking on the tear gas, tried to escape again and again from the Polytechnic University after a night of mayhem in the Chinese-ruled enclave in which roads were blocked and a bridge was set on fire.
A police officer was shot with a bow and arrow.
Many protesters, dressed in regular clothes and without gas masks, made a break for it, dodging tear gas canisters and sponge grenades, only to be forced back inside.
Some were arrested as others scrambled and tripped over barricades and fences as police pointed guns at them and threw punches.
Some were pulled back into campus by other protesters.
Chemical burns from water cannon reported
There were also running battles in the nearby commercial area of Nathan Road where activists stopped traffic and forced shopping malls and stores to shut.
Thirty-eight people were wounded overnight on Sunday, according to the city's Hospital Authority. Witnesses have remarked that some protesters have been suffering from burns from chemicals in jets fired from police water cannons.
Live video showed protesters with their hands tied behind their backs sitting cross-legged on a road as riot police stood guard in one of the busiest commercial and tourist districts in the former British colony.
Police have admitted firing three live rounds when "rioters" attacked two officers who were attempting to arrest a woman. No one was wounded and the woman escaped amid a dramatic escalation of the unrest that has plunged the enclave into chaos for almost six months.
Demonstrators angry at what they see as Chinese meddling in Hong Kong's promised freedoms when it returned to Chinese rule in 1997. They say they are responding to excessive use of force by police.
Beijing, meanwile, says it remains committed to the "one country, two systems" formula granting Hong Kong autonomy. However, China's foreign ministry this Monday issed a statements saying no one should underestimate China's will to "safeguard its sovereignty and Hong Kong's stability."
This comes as United States condemned the "unjustified use of force" in Hong Kong and called on Beijing to protect Hong Kong's freedom.
Chinese troops clear up the debris on the streets
Chinese soldiers in a base close to the university were seen on Sunday monitoring developments at the university with binoculars, some dressed in riot gear.
Chinese troops in shorts and T-shirts, some carrying red plastic buckets or brooms, emerged from their barracks on Saturday in a rare public appearance to help clean up debris.
Chinese troops have appeared on Hong Kong's streets only once since 1997, to help clear up after a typhoon last year.
Transport and school shutdown continues
The city's Cross-Harbour Tunnel, next to the Polytechnic university, linking Hong Kong island to the Kowloon peninsula, remained closed after protesters torched a bridge above the toll booths on Sunday.
Some train services and many roads across the Kowloon peninsula were also closed. All schools remain shut.
As police approached the barricaded front gate of the university before dawn, protesters retreated into the campus and started fires at the gate and a footbridge.
Some of those trapped on the sprawling red-brick campus said they would never surrender.
"We need to fight until the end. If we don't fight, Hong Kong will be over," said one 19-year-old protester to AFP.
The unrest in Hong Kong poses the gravest popular challenge to Chinese President Xi Jinping since he came to power in 2012. Xi has said he is confident Hong Kong's government can resolve the crisis and denies interfering in Hong Kong's affairs.
He has, however, blamed Western countries for stirring up the unrest.