Protests erupted across Hong Kong Friday after its embattled top official, Chief Executive Carrie Lam, invoked colonial-era emergency regulations to ban the wearing of face masks at all public gatherings. As night fell, thousands of protesters rampaged across the city, smashing shops, setting fires and occupying streets.

Malls and businesses began pulling down their shutters upon hearing the news and panic buying broke out at several supermarkets as shoppers denuded the shelves of staples, fearing a weekend of unrest ahead.

Violators of the new regulations, which apply to any kind of facial covering including paint, are liable to imprisonment for a year. The move is intended to curtail the months of anti-government protests that have rocked the former British possession and injured more than 1,100 people. But it may instead exacerbate tensions, with activists vowing to continue to defy the government.

“This is unacceptable,” one 23-year-old protester told TIME. “But we are not going to give them the satisfaction of seeing us surrender.”

Speaking at a press conference this afternoon, in front of a screen that read “Treasure Hong Kong, End Violence,” Lam said the ban would come into effect on Oct. 5. “Why do we need to have this? Because, in the past four months, we’ve seen that almost all protestors who carry out vandalism and violence cover their faces,” she said.

“The purpose is to hide their identity and evade the law and they have become more and more daring. We believe the prohibition on face covering will be an effective deterrent on radical behavior and help police in upholding the law.”

Asked if she would consider imposing more measures under the Emergency Regulations Ordinance, Lam said “The situation is a fluid and evolving one” and “If the situation continues to worsen, we will identify other means.”

Two activists, Kwok Cheuk-kin and student leader Lester Shum, quickly filed judicial challenges to the measure at the High Court.

Tweeting just before the ban was announced, prominent campaigner Joshua Wong predicted that it was “just the beginning” of draconian measures to come. In an “Open Letter to World Leaders” published on Facebook, he added: “The direct implementation of such anti-mask law, without any consultation or due process, will further expand police’s power in Hong Kong, making the city under complete police control. The procedure surpasses the legislature and is solely determined by the will of the executive, which is handpicked by Beijing.”

Joshua Rosenzweig, the head of Amnesty International’s East Asia regional office, issued a statement saying “It is thanks to the climate of fear Hong Kong authorities have created that protesters feel the need to wear masks in the first place. This ban is especially worrying in a context where protesters fear arbitrary arrest, surveillance and the indiscriminate use of tear gas and other projectiles.”

“If the police use this as a pretext to arrest more protestors, the effect among the public is that more animosity would be generated, and this poisonous relationship between protestors and police will be exacerbated,” said Willy Lam, adjunct professor at the Chinese University of Hong Kong’s Center for China Studies. “My conclusion is that this regulation doesn’t help matters. I think it will be counterproductive.”

He told TIME: “It is certainly the beginning [of some sort of crackdown]. If the protests … get worse, nobody can rule out the possibility of other parts of the ordinance being used, which could empower the administration to impose curfews and restrict certain social media communication networks.”

High school students chant slogans as they stick posters reading "all people masked" on their uniforms while protesters gather in the heart of Hong Kong's commercial district Central on October 4, 2019, after the government announced a ban on facemasks. PHILIP FONG—AFP via Getty Images

‘Our freedom of expression could be next’

Even before Lam announced the ban, protesters began gathering in the heart of Hong Kong’s banking quarter, chanting slogans of the enclave’s fourth-month-old democratic rebellion.

By the late afternoon, the crowds in the Central district had swelled considerably, and included high school students in uniform, as well as office workers in suits and brogues or Chanel sandals, clutching laptop bags and shouting “Hongkongers resist!”

Activists worked their way through the throng asking “Anyone need a mask?” and handing them out as other protesters started erecting barricades. A prominent banner commemorating the 70th anniversary of the People’s Republic was torn down and burned.

At nightfall, protesters, now numbering in their thousands, smashed several fast food outlets belonging to the Maxim’s chain, which is being targeted by after the founder’s daughter criticized the movement. Branches of Starbucks, of which Maxim’s is the franchise holder, were also attacked.

Disturbances broke out in multiple districts across the city and in the suburban hinterland. Sha Tin and Taikoo Shing stations, major transport hubs, were closed after being flooded and vandalized. At Sha Tin, black clad protesters smashed platform fittings while startled commuters looked on. A fire was started in Causeway Bay by the Sogo department store—a prominent Hong Kong landmark.

Several other subway stations were damaged and shut down, and services on one line suspended after objects were thrown on the tracks. The shopfronts and premises of businesses with mainland Chinese connections were trashed. The legislature was evacuated and non-essential staff at Police Headquarters sent home.

“I just can’t express how furious I am. I feel desperate,” a 28-year-old protester called John told TIME.

“We are worried it will expand to other laws, not just the mask ban, since they can do a lot more with this precedent now set,” said 33-year-old Abby, who works as an administrator in the financial district. “Less people may come out now [to protest]. But it will make the people who do more aggressive.”

“I think a lot of people will still wear the masks, because if we don’t it would be like silently consenting to this oppression,” said one 22-year-old student, who was worried that “Our freedom of expression could be next.”

The ban comes after Hong Kong’s worst spell of unrest in more than 50 years. Over the weekend, thousands of protesters fought running battles with police. A teenage protester was shot at close range in the chest by police but miraculously survived. Scores of others were injured and 269 people arrested.

Hong Kong’s political crisis was sparked by a now withdrawn extradition bill, which would have allowed the rendition of fugitives to mainland China for the first time. Opposition to the bill quickly grew into a democratic rebellion against the unpopular local government. Many protesters are also calling for self-determination or independence for Hong Kong, and appear more determined than ever after the government’s latest move.

Carrie Lam, said one 21-year-old recent graduate, “is only going to succeed in pushing people to take more aggressive action, as she has shown us that peaceful demonstration achieves nothing.”

—With reporting by Laignee Barron and Hillary Leung / Hong Kong

Contact us at letters@time.com.