Dozens of Hong Kong protesters have escaped a two-day police siege at a campus late Monday by climbing down a rope from a bridge to awaiting motorbikes in a dramatic and perilous breakout that followed a renewed warning by Beijing of a possible intervention to end the crisis engulfing the city.
Clashes rumbled throughout the day between protesters and police who had threatened to use deadly force to dislodge activists holed-up in the Hong Kong Polytechnic University (PolyU).
The university siege has become a battle of wills between Hong Kong's stretched police force and the constantly-innovating protest movement.
Late Monday dozens of black-clad protesters used a rope to slither down several metres on to a motorway below where they were picked up by waiting motorbike riders.
In an apparently co-ordinated effort, thousands of Hong Kongers streamed towards the campus to break the siege, as clashes simultaneously raged with police nearby in Kowloon.
It was not immediately clear how many protesters remained inside PolyU.
Monday's events were part of a new phase of violence and drama that began last week and has led to chaos throughout the city of 7.5 million people, with schools closed, train lines disrupted and major roads blocked by barricades.
China has refused to budge on any of the protesters' demands, and warned it will not tolerate dissent in the semi-autonomous city.
Chinese soldiers briefly appearing on Hong Kong's streets over the weekend supposedly to clean up debris fuelled concerns it could intervene militarily.
China's ambassador to Britain upped the ante on Monday.
"The Hong Kong government is trying very hard to put the situation under control," Liu Xiaoming said.
"But if the situation becomes uncontrollable, the central government would certainly not sit on our hands and watch. We have enough resolution and power to end the unrest."
Earlier, police made dozens of arrests as protesters made a dash for it - sometimes beating people with batons as they held them on the ground.
"Other than coming out to surrender I don't see any viable option for them," Cheuk Hau-yip, Police Commander of Kowloon West, told a press conference, before the daring breakout.
The area has been designated a 'riot' zone - a charge of rioting carries up to 10 years in prison - and Mr Cheuk reiterated that police will use "live rounds" against protesters if faced with deadly weapons.
Protests started in June as a peaceful kickback against a now-shelved China extradition bill, but have morphed into a confrontational action to defend the city's unique freedoms from perceived encroachment by Beijing.
Even by recent standards, the last few days have stood out as particularly violent, with one police officer hit in the leg by an arrow, and an armoured police vehicle torched.
Officers fired live rounds on Monday, though said they did not think anyone had been hit.
Hong Kong police routinely carry sidearms, but until now they have only used them in isolated incidents during running street clashes. Three people have been shot, none of them fatally.
They have largely relied on tear gas, water cannon and rubber bullets, but the new warning suggests a more proactive use of live rounds.
Protesters demand accountability from the police, who they accuse of heavy-handed tactics and abuse during the months of rolling unrest.
Fear gripped protesters inside the campus - whose occupation is a twist in tactics by a leaderless movement so far defined by its fluid nature.
One 19-year-old, who gave her name as "K", said there was desperation among those who remained.
"Some people were crying badly, some were furious, some agonising, because they felt hopeless as we were left no way out of the campus.
"We don't know when the police will storm in."
Protests erupted in several other parts of peninsula Hong Kong, with makeshift barricades across normally bustling shopping streets, the road surfaces strewn with bricks to hamper vehicles.
Police fired tear gas at groups who had gathered in the Tsim Sha Tsui and Jordan areas, where they also made a number of arrests, in hotspots active deep into the evening.
"Blossom everywhere" campaign
The unrest has rocked previously stable Hong Kong, tipping the international financial hub into recession and frightening off tourists.
Violence has worsened this month, with two men killed in separate incidents.
Demonstrators last week engineered a "Blossom Everywhere" campaign of blockades and vandalism, which shut down sections of Hong Kong's transport network and closed schools and shopping malls.
In his most strident comments on the crisis, Chinese President Xi Jinping said it threatened the "one country, two systems" model under which Hong Kong has been ruled since the 1997 handover from Britain.
On Saturday, dozens of soldiers from the Chinese People's Liberation Army briefly left their Hong Kong barracks to help clean-up the streets.
It was a rare and symbolic operation, as the troops are normally confined to barracks and are meant to be only called out in a time of emergency.