Hong Kong police surround university as violent standoff with students continues

A photo sent to CNN from within Hong Kong's Polytechnic University shows what appears to be a makeshift bomb made from a gas canister with bolts attached.

CNN cannot confirm that it is in fact a viable explosive device, or that it still contains volatile gas.

A police spokesperson confirmed to CNN that gas canisters have been used during protests as weapons against them.

The management of Hong Kong Polytechnic University issued a statement Sunday saying "dangerous chemicals" had been stolen from laboratories and condemned the protesters' "illegal acts and violence" in the campus which has, they say, "been widely damaged."

Arrests are continuing in the area around Hong Kong's Polytechnic University while an unknown number of protesters are still occupying the campus.

In an attempt to draw police away from the university, a call has gone out on the online Reddit-like platform LIHKG for demonstrations elsewhere in the city.

LIHKG is regularly used by protester groups to coordinate and plan actions.

Supporters of the demonstrators used the same tactic late on Sunday night to try and distract police from the university, starting fires and building barricades in surrounding districts.

Already this morning there have been gatherings of protesters in Jordan, to the north of Polytechnic University, where they have been digging up bricks.

The editor of the state-run tabloid Global Times took to Twitter early this morning to call for Hong Kong police to be given permission to shoot protestors with live rounds.

"Hong Kong looks like a battlefield tonight," editor Hu Xijin said on his official Twitter, after posting a video of an armored car being set alight by protesters.

Hong Kong police warned protesters during the late night siege that they would use live rounds if those inside the campus didn't stop throwing petrol bombs and shooting arrows.

So far only one live round was confirmed fired late on Sunday, after a car tried to ram police lines in the Kowloon district of Jordan.

Dozens of protesters have already left the fortified campus of Hong Kong Polytechnic University (PolyU) this morning but there are still more inside who are unable to leave.

One 23-year-old protester who asked not to be named said that he was stuck on an undisclosed part of campus with about 20 other demonstrators. An unknown number of other protesters, many of whom are thought to be students, remain holed-up in other parts of the large central campus.

The protester, who is not a student at PolyU, said that they were tired and scared, adding he had seen people injured with tear gas and rubber bullets. He said that while some protesters still have hope, there is an expectation now that they will be arrested.

He said his parents thought he was at his girlfriend's house and he didn't know what he'd tell them.

"Currently those around me we just want to escape, we don’t have any equipment to help us fight," he said.

Students and protesters at the Polytechnic University (PolyU) have been facing off with police for nearly 24 hours -- but many haven't left the campus for days.

Earlier last week, hundreds of riot police at the Chinese University of Hong Kong (CUHK) fired more than 1,567 canisters of tear gas during a chaotic and ultimately suspended clearance operation.

Protesters also moved to occupy other universities like PolyU, with sporadic clashes breaking out there since Thursday morning.

On Friday night, protesters suddenly evacuated CUHK, bringing the four-day occupation to an end -- but only beginning the weekend-long occupation of PolyU.

Protesters accuse police of laying "siege" to CUHK and PolyU. Police say they were only trying to stop protesters from throwing objects onto roads and disrupting traffic at CUHK. They have labeled occupied universities a "breeding ground for criminals and rioters" and a "weapons factory."

On Friday, CNN's Helen Regan spent the day with protesters at PolyU, as they began fortifying the campus. Read more about the days-long occupation from inside the university here.

A Hong Kong police officer was shot with an arrow yesterday during clashes at the Polytechnic University campus.

As violence has escalated in recent days, protesters have begun using bows and arrows against the police, and authorities said a media liaison officer was hit in the leg with an arrow during a skirmish Sunday afternoon.

The man who was shot with an arrow was sent to hospital for treatment, according to the police statement.

Students and protesters occupying the universities have used other unorthodox weapons this past week, including javelins and equipment taken from campus gym stores.

Police in Hong Kong released a statement on Monday morning denying that they had "raided" the Hong Kong Polytechnic University, where they are currently facing off with students (some of whom are trying to evacuate).

The police statement called the raiding accusation "totally false," and accused "rioters" of throwing petrol bombs and setting objects aflame.

Read the statement:

As the sun rises today, the streets around Hong Kong's Polytechnic University are covered in litter and debris from the weekend's clashes.

Scorch marks, bricks and abandoned umbrellas cover the area around the campus, which is currently the site of an almost 24-hour siege between police and protesters.

It's a surreal sight in one of the world's most urbanized financial hubs.

After almost 24 hours of violent clashes between police and protesters, the total number of arrests and injuries is still unknown.

The president of the university's student union said in a statement posted to Facebook this morning that some protesters had been injured or were suffering from hyperthermia.

"We have tried to communicate with school authorities, but we have not received any reply after more than two hours," the president Derek Liu said.

CNN has seen several black-clad young people wearing protective gear being taken away by police, but so far there has been no official numbers from the authorities.

Police said on Sunday that those holding the Polytechnic University were "rioters," and warned that rioting carried a much heavier charge than illegal assembly.