With the metro suspended since Friday night, protesters, some wearing banned masks, have taken to the streets.

Protesters – some wearing newly banned face masks – have again taken to the streets of Hong Kong, despite the unprecedented suspension of the city’s public transit following a night of violent demonstrations.

The most recent unrest was sparked by Chief Executive Carrie Lam decision to invoke emergency powers to ban protesters from wearing face masks on Friday. The ban, which prohibits the masks at sanctioned and unsanctioned rallies, officially went into effect on Saturday.

The transit suspension, which threatened to grind the semi-autonomous trade and financial hub of 7.5 million to a halt, did not stop protesters from staging marches and flashmobs at multiple locations around the city on Saturday.

In some places, they formed human chains, singing and chanting as they marched.

“The anti-face mask law is the first step,” protester Hosun Lee told AFP.

“If we don’t stand up and resist, then it could be that 2047 has already come,” he added, referencing the year semi-autonomous Hong Kong is set to fully become part of the Chinese mainland.

The latest unrest in four months of demonstrations began the night before, shortly after Lam’s announcement, with large crowds of office workers initially blocking roads in the heart of the central commercial district.

Later that evening, demonstrators vandalised subway stations, started street fires and smashed the windows of pro-China businesses.

Police used tear gas in multiple locations to disperse protesters who had taken over roads.

MTR Corp, which operates the public transport network that serves about five million passengers each day, said protesters had set fires at stations on an empty train and injured two staff during the night’s violence.

“As we are no longer in a position to provide safe and reliable service to passengers in the circumstances, the corporation had no choice but to make the decision to suspend the service of its entire network,” the company, known for operating one of the world’s most efficient rail systems, said in a statement.

The events were a “very dark night for Hong Kong” that made “society semi-paralysed”, Lam said in pre-recorded television announcement on Saturday, adding that the violence justified her invocation of emergency powers.

“The extreme violence clearly illustrated that Hong Kong’s public safety is widely endangered,” she said.

14-year-old shot

Also overnight, in the northern district of Yuen Long, a police officer opened fire when he was surrounded while in his car and attacked by protesters, with a petrol bomb exploding at his feet, authorities said.

“A large group of rioters attacked a plain-clothes 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-defence,” the police said in a statement.

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In the same district, a teenage boy was shot and wounded by a live round, the South China Morning Post reported, citing a medical source.

It was not immediately clear if that round was linked to the plain-clothes officer who opened fire.

The United Nations High Commissioner for Human Rights Michelle Bachelet said on Saturday that she has called for an independent investigation into the “acts of violence including shooting” committed during the protests.

She added she “strongly condemned” the violence from both sides, saying “those responsible should face due process”.

“I reiterate my call on Hong Kong authorities and the people of Hong Kong to engage in genuine and transparent dialogue that can really contribute to a meaningful outcome of this situation,” she said.

Face-mask ban

Friday’s demonstrations erupted hours after Lam invoked colonial-era emergency powers – last used more than 50 years ago – to ban face masks at rallies, which demonstrators use to conceal their identities.

Since June, Hong Kong has been engulfed in anti-government protests triggered by a since suspended bill that would have allowed the extradition of accused individuals to mainland China for trial.

The protests have now morphed into a wider pro-democracy movement.

The anger has been fueled by officials’ refusal to address protesters’ demands for an independent inquiry into alleged police brutality in suppressing the protests, amnesty for all those charged with offences stemming from participating in protests, and a retraction of police claims that protesters are guilty of rioting.

Critics say Lam’s invocation of emergency powers was a major step towards authoritarianism for Hong Kong, which has been governed by China under a “one country, two systems” framework since British colonial rule ended in 1997.

Beijing has hailed the ban as “extremely necessary”.

Protester wearing mask smashed windows of Chinese banks on Friday night. [Tyrone Siu/Reuters]

Kris Cheng, the editorial director of the Hong Kong Free Press, said protesters are not that concerned with the ban, which carries a penalty of up to a year in prison and a fine of $3,200.

“What’s more worrying is … that there may be further measures for the government, including extending detention hours to 96 hours, including extra funds to police, including banning weapons, banning protesters to hold certain kinds of weapons,” Cheng told Al Jazeera.

“So this may be the only the first step for the government to use the emergency law to set up all of the new laws they want to enact.”

Two activists filed legal challenges late on Friday against the ban on the grounds that it would instil fear and curtail freedom of assembly, but a court denied their request for an injunction.

The demonstrations on Saturday were mostly peaceful as of early evening, with some reports of vandalism.