Hong Kong police have staged a water cannon demonstration as pro-democracy street protests stretched into their 10th week with no sign of either side backing down.

The demonstration of specially equipped armoured cars came after another weekend of protests at Hong Kong's bustling international airport and on the streets of one of the city's main shopping districts.

Also today, Beijing slammed violent protesters who had thrown petrol bombs at police officers and linked them to 'terrorism'.

An anti-riot police vehicle equipped with water cannons is seen spraying water during a demonstration at the Police Tactical Unit Headquarters in Hong Kong today

The demonstration of specially equipped armoured cars came after another weekend of protests at Hong Kong's bustling international airport and on the streets in downtown

Legislators and journalists were invited to witness the display of extreme crowd control tactics

A dummy as a protester is showered by an anti-riot vehicle equipped with water cannon

Legislators and journalists were invited to witness the display of extreme crowd control tactics, which Amnesty International warned last week could lead to serious injuries if misused within Hong Kong's confined spaces.

Hong Kong police has also revealed a type of spraying liquid dye that could help them catch protesters who wear masks to conceal their identity.

Once sprayed onto a person at a demonstration site, the liquid dye could stay on their skin or clothing, which would make it easier for the police to identify relevant individuals if necessary, the police said.

Such liquid dye, said to be harmless and edible, could be added into water or tear gas solution, said a spokesperson recently.

All remaining flights out of Hong Kong International Airport on Monday have been cancelled after protesters swarmed to a terminal building to stage a sit-in. Pictured, demonstrators surround banners that read: 'Those charge to the street on today is brave!' (centre top) and 'Release all the detainees!' during the peaceful rally at the arrival hall of the airport today

Hundreds of Hong Kong protesters have started three days of rallies at the city's busy airport since Friday. The city's streets witnessed another weekend of violent clashes between activists and police. One female demonstrator faces losing her eye after being hit by a bean bag round by the police in Tsim Sha Tsui on Sunday. The incident has sparked more anger in public

A protester covers her one eye with a gauze during the mass demonstration at Hong Kong International Airport today after news of a woman shot in the eye during a protest shocked the financial hub. Pro-democracy leaders were calling for as many as one million people to head to the Hong Kong airport today after 40 people were injured across the city over the weekend

A protester lays on the floor as she occupies the arrival hall of the Hong Kong International Airport during the mass demonstration today. Police have also reported injuries among their ranks during weekend's clashes, including eye irritation from laser pointers and burns from a petrol bomb. The city's anti-extradition-bill protests have lasted 10 weeks so far

Hong Kong's Airport Authority has cancelled all flights not yet checked in by Monday afternoon and said traffic on roads to the airport was very congested and car park spaces were full. Demonstrators attend a protest at the departure hall today

About 5,000 protesters rallied at the Hong Kong airport today to denounce alleged police violence after another weekend of clashes between activists and police.

One female protester faces losing her right eye after being shot in the face with a bean bag round during a clash between police and demonstrators on Sunday.

Hong Kong's Airport Authority has cancelled all flights in and out of the city as a result. The cancellation period is due to extend until tomorrow morning local time.

The city's flag carrier Cathay Pacific today warned its staff that they could be fired if they 'support or participate in illegal protests' as the airline comes under pressure from Beijing.

All flights in and out of Hong Kong on Monday have been cancelled after thousands of pro-democracy protesters flooded the city's airport to denounce police violence. Pictured, anti-extradition bill protesters rally at the departure hall of the airport

A passenger waits at the departure hall as protesters rally at the terminal building. The abrupt shutdown at one of the world's busiest hubs came as the Chinese government denounced some of the violent demonstrations as 'terrorism'

Passengers wait at the departure gate of Hong Kong airport as anti-extradition bill protesters occupy the floor during a protest today. 'Airport operations at Hong Kong International Airport have been seriously disrupted as a result of the public assembly at the airport today,' the airport authority said in a statement

A man looks at the flight information board shows outbound flights was cancel at the Hong Kong International airport

'Hong Kong's radical demonstrators have repeatedly used extremely dangerous tools to attack police officers, which already constitutes a serious violent crime, and also shows the first signs of terrorism emerging,' said Yang Guang from China's Hong Kong and Macau affairs office

Hong Kong is at a critical juncture after two months of anti-government street protests and violence there must stop, China's Hong Kong and Macau affairs office said on Monday.

Increasingly restive protests have plunged Hong Kong into its most serious political crisis in decades, posing a challenge to the central government in Beijing.

Yang Guang, a spokesman for the office in Beijing, delivered a televised address in which he backed police handling of the protests and said that those who care about the city should come out against violence.

'Hong Kong's radical demonstrators have repeatedly used extremely dangerous tools to attack police officers, which already constitutes a serious violent crime, and also shows the first signs of terrorism emerging,' said Yang Guang.

'This wantonly tramples on Hong Kong's rule of law and social order.'

Amnesty International warned last week that the anti-riot water cannon vehicle could lead to serious injuries if they are misused within Hong Kong's confined spaces

Hong Kong police started road-testing the anti-riot trucks in the city's streets from last month

The demonstration comes after Hong Kong police recently revealed an anti-riot liquid spray

During the weekend protests, website Hong Kong Free Press showed footage of one arrest that appeared to include officers pinning a demonstrator to the ground. The young man, who said his name was Chow Ka-lok and asked for a lawyer, was shown with a bleeding head wound and said he had a broken tooth.

Police have also reported injuries among their ranks, including eye irritation from laser pointers and burns from a petrol bomb.

Protesters hurled bricks at officers and ignored warnings to leave before tear gas was deployed in the Sham Shui Po area, police said, calling a march there an 'unauthorised assembly'.

Tear gas was also deployed in central Hong Kong on both sides of Victoria Harbour, in the Tsim Sha Tsui area on the Kowloon side and in Wan Chai on Hong Kong Island. At one point, protesters blocked the entrance to a plaza to prevent police from entering.

A train station in Kwai Fong filled with smoke after about a dozen police officers fired tear gas inside. It was not clear how many protesters were inside the station at the time, but it has been rare for officers to fire tear gas indoors.

Earlier, a large group of mostly young protesters marched down the middle of Hennessey Road, a main shopping street in the Causeway Bay area, as a rally was held in nearby Victoria Park. Many wore face masks to shield their identities, and a few had helmets. Others just carried backpacks over the black T-shirts that have become their uniform.

One Hong Kong police officer demonstrates the new equipment in a video released this month

Such liquid dye, said to be harmless and edible, can be added into water or tear gas solution

The liquid dye can be poured into a portable spraying device or a water jet pack to be used

The protest movement's demands include the resignation of the Chinese territory's leader, Carrie Lam, democratic elections for her successor, the release of those arrested in earlier protests and an investigation into police use of force.

A former British colony, Hong Kong was returned to China in 1997 under the principle of 'one country, two systems,' which promises the city certain democratic rights not afforded to people on the mainland. But in recent years, some have accused the Communist Party-ruled central government of steadily chipping away at their freedoms.

Banners at the rally in Victoria Park read 'Give Hong Kong back to us' and 'Withdraw the evil law,' the latter a reference to an extradition bill that was the original spark for the protests. A large crowd sat under umbrellas, which are both a protest symbol in Hong Kong and protection from the summer heat.

Over the weekend, protesters hurled bricks at officers and ignored warnings to leave before tear gas was deployed in Sham Shui Po, police said, calling a march there 'unauthorised'

At the airport, a flight attendant protesting on his day off, who gave only his surname, Lau, said heavy-handed police tactics had alienated some among the public.

'The police have told a lot of lies to Hong Kong people. We cannot believe them any more. We have to come here to protest,' Lau said. China has reportedly threatened to bar air crew who take part in protests from its air space.

Another protester, who identified herself only as Bea, said she had taken the day off work to express her outrage.

'I feel that I have to do something… It's just too sad to see what has happened. The police action has gone totally nonsensical,' she said.