Thousands of masked, pro-democracy protesters took to the streets of Hong Kong on Saturday in continued protest of a new government ban on wearing face masks.

Unsanctioned marches and flash mob protests took place Saturday following a night of violent unrest that resulted in the suspension of Hong Kong's mass transit rail system.

Chief Executive Carrie Lam condemned the violence in a video. "We cannot allow rioters any more to destroy our treasured Hong Kong," she said.

Watch video 01:12 Why Hong Kong demonstrators defy the face mask ban

Lam said she invoked the restriction on masks under the Emergency Regulations Ordinances, a colonial-era plan that allows her to circumvent the legislature and enforce any regulations during a time of emergency or public danger.

Thousands of angry demonstrators filled the streets in the central business district on Friday evening shouting "Hong Kong, resist."

The ban applies to all public areas where protesters might gather. The prohibition means the wearing of full or partial face coverings, including face paint, at public gatherings is punishable by one year in jail.

Watch video 01:58 Share Face mask ban in Hong Kong Send Facebook google+ Whatsapp Tumblr linkedin stumble Digg reddit Newsvine Permalink https://p.dw.com/p/3Ql2w Hong Kong's face mask ban comes into effect

Nevertheless, protesters continued to vandalize subway stations, start fires and smash the windows of pro-China businesses as clashes erupted throughout Friday evening. Police used tear gas to quell demonstrators.

"The government doesn't listen to us. So we are upping our game," 32-year-old protester Nathalie told the AFP news agency as demonstrators began to trash the MTR transit station in the previously calm neighborhood of Tseung Kwan O.

'Very dark night'

In the northern district of Yuen Long, a police officer opened fire when he was surrounded in his car and attacked by locals. A petrol bomb exploded at the officer's feet.

Read more: 'Hong Kong mob' — How mainland Chinese see the democracy movement

"A large group of rioters attacked a plainclothes police officer in Yuen Long district. The police officer fell onto the ground and was beaten up by the group. Facing serious threat to his life, he fired one shot in self-defense," police said in a statement.

Hong Kong's embattled leader Carrie Lam has described the overnight rioting as "a very dark night" for the semi-autonomous territory. She said, "Everyone is worried and scared."

In a pre-recorded televised address broadcast Saturday, Lam defended the legality of the ban criminalizing the wearing of masks at public rallies. Describing Hong Kong as being in the grips of "unprecedented violence," Lam said that "to protect citizens' daily lives and freedoms, I cannot allow the small minority of rioters to destroy that."

Police responded with tear gas, as protesters took shelter

Teenager shot, train lines remain closed

In Yuen Long, a teenage boy was also shot and wounded, the South China Morning Post reported, citing a medical source.

The territory's entire subway network was suspended on Friday night. By Saturday morning, train services were also closed, including the airport line, with the rail operator saying it would analyze the damage caused to stations before deciding when to reopen.

Demonstrations were planned across Hong Kong on Saturday with two major protests scheduled for Saturday afternoon in Causeway Bay on Hong Kong island and across Victoria Harbour in Tsim Sha Tsui.

Both are popular shopping districts that have borne the brunt of demonstrations in recent weeks.

sri,jsi,kp/ng (AFP, AP, dpa)

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