Image source, EPA

Here's a quick recap of the major developments in Hong Kong:

• Riot police again fired tear gas against protesters trying to break through police lines near the Polytechnic University
• A number of people were arrested and injuries reported

• In the past week, the campus has turned into a battleground as long-running anti-government protests become more violent
• Hong Kong's Chief Executive Carrie Lam condemns “rioters”, urging protesters to obey police
• China warned against any foreign interference

We're now pausing our live coverage but you can get all the latest from Hong Kong on our main story.

Images from Hong Kong Polytechnic University show medics carrying people out of the university building.

On Monday afternoon, the Hospital Authority said 24 people aged between 16-84 were injured with four in serious condition across Hong Kong.

Image source, Getty Images

Image source, Reuters

More from the Chinese Ambassador to the UK's news conference in London. Liu Xiaoming accused the British government of taking sides in the Hong Kong protests.

"We have made our position known to the British side when they have made irresponsible remarks on Hong Kong. I think when the British government criticise Hong Kong police, criticise the Hong Kong government in handling the situation they are interfering into China's internal affairs.

"They look like they are balanced but as a matter of fact they are taking sides. That is our position."

As he was speaking at the Chinese embassy, the UK Foreign Office issue a statement, saying the government was seriously concerned by the escalation in violence from both the protesters and the authorities.

The UK's Foreign and Commonwealth Office said the government was "seriously concerned by the escalation in violence from both the protesters and the authorities around Hong Kong university campuses".

"It is vital that those who are injured are able to receive appropriate medical treatment, and that safe passage is made available for all those who wish to leave the area," it added in a statement.

"We need to see an end to the violence, and for all sides to engage in meaningful political dialogue ahead of the District Council elections on Sunday."

Hong Kong Free Press news website reports that at about 19:20 local time (11:20 GMT) riot police again fired tear gas against protesters trying to break through police lines near the Polytechnic University.

The Chinese Ambassador to the UK, Liu Xiaoming, has said the escalation of violence has pushed Hong Kong into an "extremely dangerous situation".

At a news conference in London, Mr Liu firmly supported Hong Kong's police, saying the illegal protests had "nothing to do with so-called democracy or freedom".

"The nature of the issue is that a few violent offenders have disrupted law and order in Hong Kong, attempted to destabilise Hong Kong and undermine one country, two systems," he said.

"The extreme violent offences have trampled on the rule of law and disrupted public order in Hong Kong."

He also warned against any foreign interference into China's domestic issues.

Hong Kong's public broadcaster RTHK is quoting the Secretary for Constitutional and Mainland Affairs, Patrick Nip, as saying the government's position is clear it will try its very best to ensure that district council elections can go ahead as planned on Sunday.

"However, the situation in the past weekend has obviously reduced the chance of holding the elections as scheduled and I'm very worried and anxious about this," Mr Nip says.

"I must say that postponing the elections is a difficult decision to make and we will not take this step unless absolutely necessary."

Postponing or cancelling the elections - in which the pro-Beijing camp is expected to do badly - could further inflame the protests.

Footage has emerged showing a tearful mother collapsing to the ground outside the Polytechnic University, while pleading for her children's safety.

Several protesters were arrested while trying to leave the campus surrounded by police, who used tear gas and rubber bullets. It was the third time protesters had tried to leave.

Earlier, pro-democracy lawmaker Ted Hui, who is on the campus, said there were up to 1,000 protesters on the site.

South China Morning Post's Jeffie Lam says police have pledged to stop enforcing the anti-mask law, external, after the High Court ruled that the ban on masks was unconstitutional.

The controversial rule was brought in by the government in October, using a colonial-era emergency law.

But protesters have largely defied it and continued to wear masks to hide their identities.

Hong Kong's Chief Executive Carrie Lam says she visited the police media liaison officer who was injured by an arrow on Sunday and wished him a speedy recovery.

In a Facebook post (in Chinese), she also condemns “rioters” for the “rising levels of violence”, and urges them to obey police.

The chief superintendent Kwok Ka-chuen also took the opportunity to address a controversial incident from the weekend.

An officer was shot with an arrow outside the campus, Earlier, striking pictures had been circulating of protesters using bows and arrows.

He had strong words.

"Without a doubt, this is a murderous act. There’re many reporters in the same area. The arrow could have killed our officer or anyone in the surrounding. We express the strongest condemnation against this indiscriminate violence," he said.

Police are looking for a peaceful way to end the standoff, said Chief Superintendent Kwok Ka-chuen of Police Public Relations Branch.

"As long as these masked rioters give up their weapons, drop their weapons, follow police instructions and shoulder their legal responsibilities, the police have no reason to use force."

Police added that anyone who surrenders to police will be arrested for rioting, a charge that carries a maximum sentence of 10 years in prison.

There is a strong smell of tear gas near Queen Elizabeth Hospital in Jordan, South China Morning Post reports.

It says medical staff are distributing and putting on face masks to protect themselves against hazardous substances.

“We have asked colleagues and patients to close the windows,” a nurse is quoted as saying. “Seems the hospital is installing some air ventilation machines around the place. I hope it’s not too late.”

Some patients leaving the hospital are covering their mouths and noses, the SCMP adds.

We've seen images like this before coming out of Hong Kong, but the past week has been quite intense and there's been a stream of even more close-up and emotive photography. From today, here are some faces of people arrested by police as they tried to leave the university.

Image source, Laurel Chor/Getty Images

Image source, Laurel Chor/Getty Images

Hong Kong Polytechnic University - also known as PolyU - is one of Hong Kong's oldest and most well known universities. In the Times Higher Education World University Rankings it comes in at 171. A former chief executive of Hong Kong, CY Leung, even earned a degree from there.

It sits centrally, in the district of Hung Hom, in Kowloon - and at the mouth of the entrance to Hong Kong's busy cross-harbour tunnel which burrows under the sea providing cars passage to Hong Kong island.

For that reason it's actually a very strategic location

Police are not just firing tear gas at those attempting to leave PolyU. At Tsim Sha Tsui, a major shopping hub close to the campus, protesters are engaging with police as well, as this scene captured by BBC News Chinese reporters shows.

Grace Tsoi
BBC World Service, Hong Kong

A protester holed up inside PolyU who wishes to stay anonymous has spoken to the BBC.

According to him about 300 to 500 people are still inside the Polytechnic University campus.

“The campus is calm now but there is underlying tension. It’s like we are stuck inside a chamber and there’s no escaping,” he said, adding that he has been inside the campus since 3pm yesterday.

He is an alumnus in his 30s and wanted to offer counselling service for people inside.

He said supplies inside the campus are running low, especially first aid supplies and drinking water.

When we talked on the phone, he was finding ways to leave the university and had to cut the interview short. “Anyone leaving will be arrested,” he said.

“I am worried, but we can only try.”

In Yau Ma Tei, the area in the south of the Kowloon Peninsula, protesters continued their cat-and-mouse game with police as they occupied roads, set up barricades and dodged tear gas, Hong Kong's South China Morning Post (SCMP) reported.

It said the entire intersection between Jordan Road and Nathan Road was blocked with bricks and other debris.

Jordan Road is a main route to Queen Elizabeth Hospital, and officials earlier urged protesters not to block roads needed by emergency services.

It's a regular thing now and police once again provided reporters with the numbers of arrests and weapons used in the last few days:

• Arrests in the protests so far: 4,491 people, 3,395 male and 1096 female
• Their ages range from 11 to 83 years old
• They have been arrested for rioting, arson, assaulting police among other charges

This past weekend police arrested 154 people, 103 male and 51 female, aged between 13-54.

As protesters outside the university rally to pressure police, they've been shouting a slogan: "Save the students!"

As we have posted about earlier, it remains unclear though just how many of those inside PolyU are current students of the university. But it's still a potent rallying cry for people out on the streets.