HONG KONG (BLOOMBERG, REUTERS) - The president of a Hong Kong university that has been the site of a stand-off between protesters and police said some 100 protesters remain on campus, hours after the city's security chief urged those still holed up since the weekend to surrender.

Among those who are still at the Hong Kong Polytechnic University (PolyU) campus were 20 students from the university, Professor Teng Jin Guang told reporters outside the campus on Wednesday (Nov 20) afternoon.

Reiterating the hope for a peaceful resolution to the situation, Prof Teng said the biggest concern is for the remaining protesters to leave the campus safely.

"If any protesters are still worried about the process of coming out, I can assure you, because I have the assurance from the police force, if you come out, myself or one of my team members will meet you outside... We will accompany you to the police station to make sure that the whole case is going to be processed peacefully, fairly and humanely," said Prof Teng.

When asked by the media, Prof Teng said he was not aware of any deadlines for people to leave the campus before police would enter the university.

Earlier on Wednesday, Hong Kong Security Secretary John Lee urged protesters still on the PolyU campus to surrender to the police "in a peaceful and orderly manner", adding that the incident "cannot drag on forever".

Almost 900 people had surrendered themselves to police, 300 of which were under the age of 18, Mr Lee told reporters outside the Legislative Council chamber.

Police will work with other departments to try to clear road blocks and re-open surrounding roads near PolyU and the nearby Cross-Harbour Tunnel, he said.

Mr Lee also said that authorities had arrested 730 people for various crimes on Tuesday, although he did not say whether that included the PolyU protesters.

Those leaving the campus who are above 18 years old would be arrested on suspicion of rioting, but police would investigate each case thoroughly before deciding what to do next, said Mr Lee.

Police also reiterated that all persons under 18 years old leaving the campus are required to be photographed and have their personal particulars registered. They will not be arrested at scene but the force reserves every right to take any legal actions in the future.

The last band of anti-government protesters who remained inside the besieged university were weighing a narrowing range of options early on Wednesday as police outside appeared ready to simply wait them out.

Some protesters simply surrendered, while others were nabbed in escape attempts that included trying to clamber down ropes onto waiting motorbikes or sneak through sewer pipes.

Police searched for potential escapees overnight with spotlights rather than using the tear gas and rubber bullets that had marked clashes in recent days, heeding calls from Hong Kong leader Carrie Lam for a humane end to a siege that saw the most intense clashes since the protests escalated more than five months ago.

They also tightened barricades in the streets surrounding the university, making them secure enough to be visited late on Tuesday night by the force's new commissioner, Mr Chris Tang, at the end of his first day on the job.

Mr Tang earlier urged the support of all citizens to end the unrest triggered by fears that China's central government is stifling the former British colony's freedoms and extensive autonomy guaranteed in its handover to Chinese rule in 1997.

Chinese leaders say they are committed to the "one country, two systems" formula and have accused foreign countries, including Britain and the United States, of stirring up trouble.

The unrest marks the most serious popular challenge to Chinese President Xi Jinping since he came to power in 2012.

Some protesters emerged as the sun rose above the campus after a night spent sleeping on yoga mats to express a range of feelings, from defiance to uncertainty.

"I already know where I will hide," a 19-year-old student, who gave his name only as Paul, said as he emerged in a hoodie, shorts and slippers to ask about breakfast in the canteen.

Others mulled hiding in the maze of campus buildings, as they said a teacher had advised them to do.

"I have enough food for at least a week and then will see what happens," he said.

Two protesters in full body armour, wielding metal rods, were going to get some sleep in the library after their night shift watching police movements outside.

"We need some energy to get ready for the big fight. Now that there's not many of us left, they may want to come in," said a former student named Marc, 26.

"We know this place, it's our home and it is a maze. And we have weapons. We're not going to give up now, it's too late for that," he said.

Protesters still have stocks of petrol bombs, bows and arrows and other makeshift weapons after a weekend of fiery clashes.

One protester practised firing arrows at a campus tower shortly after dawn.

The university on the Kowloon peninsula is the last of five that protesters had occupied to use as bases from which to disrupt the city over the past 10 days, blocking the central Cross-Harbour Tunnel outside and other arteries.

"It's still incredible we defended it for such a long time," said a 21-year-old student named Ricky. "Since the police have taken control, many started to feel afraid and left, and now many of us feel desperate and unhappy because we lost some support."