Hong Kong police upped the ante against anti-government protesters early Sunday evening by making the unprecedented move to deploy water cannon vehicles to a lawful protest that degenerated into clashes, as the city's ongoing anti-government movement has stretched into its 12th weekend.

At around 18.00 local time (10.00 GMT), two water cannon vehicles arrived in the residential district of Tsuen Wan in the New Territories, where a march took place Sunday afternoon.

Shortly after 18.00, the police fired water cannon for the first time trying to clear makeshift barriers on a major road but to no avail.

It had been a widely anticipated moment over the past few weeks since it became known in late July that the police had completed testing of equipment on three water cannon vehicles and would be deployed in August to handle protests.

There were concerns that the anti-riot trucks would cause widespread injuries among pro-democracy activists, who have been taking to the streets over the past 11 weeks in a protest movement that has plunged Hong Kong into its biggest crisis in decades.

Teargas was fired for the first time of the day at around 17.30. This was followed by many more rounds after the water cannon vehicles were launched into operations. Many protesters fled the scene after 18.00.

The march kicked off at 15.00, which went from the working class area of Kwai Chung to Tsuen Wan. It was initially banned by the police but organizers later won their appeal and made a compromise over the route.

At around 16.00, some protesters started to create makeshift barricades on roads to keep police at bay.

The march came just a day after an authorized march devolved into clashes between protesters and police in three different districts, leading to the arrest of 29 people. Ten people from the protest areas of Wong Tai Sin and Kwun Tong were admitted to public hospitals Saturday night.

As with Saturday, Hong Kong's underground operator, the MTR Corporation, announced on Sunday morning the temporary closure of three metro stations encompassing the protest route, citing concerns over safety of passengers and MTR staff.

It was the second day in a row the MTR made the unusual move, which came just a few days after China's state-run media outlets criticized the MTR Corporation for being an "accomplice to rioters" by arranging additional trains for protesters to board during police clearance operations.

Earlier on the day, family members and relatives of the embattled Hong Kong police turned up at an unprecedented rally, calling for the government to solve the ongoing political crisis without making the police force a scapegoat, and for frontline officers to behave.

Braving rainy weather, dozens of people assembled at a public square in the city center at 14.00 local time (6.00 GMT) for the first ever rally devoted to families of the police force since the anti-extradition law movement erupted in Hong Kong in June.

The event, entitled "Return police to people", was organized by Police Relatives Connection, an online group recently formed by some netizens who have family members or relatives working in the police force.

One of the objectives of the group is to restore the tarnished reputation of the force, which has come under severe criticism since June for their alleged brutality and misconduct in protests.

Chanting "Return police to power!", the demonstrators marched to Hong Kong chief executive Carrie Lam's and the police headquarters to hand in a petition letter following the hour-long rally.

They raised five demands, including the call for the government to "settle political issues with politics", the setting up of a police-citizen communication platform to ease strained relations between the two, and the call for frontline police officers to "enact their own self-discipline for the enforcement of law? without malice or ill-will toward none in order to protect the public".

They also called for the establishment of an independent investigation commission to probe various issues in protests, echoing one of the five demands repeatedly raised by pro-democracy protesters.

A growing number of Hong Kong people from different quarters, including business leaders, lawyers and doctors, have also voiced the same demand, although the government has yet to heed the call.

Police associations also oppose the idea, saying the existing mechanism, a police body called the Independent Police Complaints Council, suffices.

Among those attending the rally was a young man whose father is a policeman.

Declining to give his name, he told Efe: "Political issues should be settled through political solutions. The police should not be used as a tool."

"My dad and I have different political positions, we avoid talking about politics these days.

"He thinks protesters are creating chaos by protesting and the police are doing the righteous thing to enforce law.

"Yes, people have disrupted public order, but there have been cases of arbitrary arrest by the police and some policemen have lost self-control.

"It’s not for them to say whether their behavior is acceptable or not, there should be an independent inquiry body to find out the truths," the young man concluded.

Another participant of the rally with a family member in the police force told how she felt hurt at a home party when a six-year-old guest blurted out "police are bad people".

"I was scared. Is this the kind of future Hongkongers want to have? Is this the kind of social divide we are going to have to face?" she said to the crowd.

Since June, Hong Kong has been in the throes of its worst political crisis in decades, sparked by the extradition bill that would have enabled fugitives to be extradited from Hong Kong to mainland China to face trials under China's state-controlled judicial system.

Though the proposed law has been declared "dead" by Lam, the anti-extradition bill campaign has morphed into a broader movement seeking to reverse a general decline in freedoms and investigate alleged police brutality and violations of law.

On 13 August, a spokesperson for the UN High Commissioner for Human Rights issued a statement raising concerns that Hong Kong police had employed "less-lethal weapons in ways that are prohibited by international norms and standards", including firing teargas in crowded, enclosed areas and directly at protesters, "creating a considerable risk of death or serious injury". EFE