HONG KONG (NYTIMES) - The two Hong Kong protesters were dressed head to toe in black, their faces covered in masks. They smashed their Molotov cocktails into the lobby of a public housing estate, and flames and smoke began spewing out.
This was no scene from the protest violence last year over Beijing's dominance of Hong Kong's affairs. This was on Sunday (Jan 26), and the firebombing was incited by anger over the coronavirus that originated in Wuhan, China - and plans by the Hong Kong government to use the unoccupied housing block as a quarantine area.
Angst and anger fuelled by the coronavirus outbreak, which has killed more than 100 people on the mainland and has eight confirmed cases in Hong Kong, is compounding the bitterness from months of protests against Chief Executive Carrie Lam's leadership.
The prospect of a new avenue for criticism of Hong Kong's government, as well as lingering trauma from the severe acute respiratory syndrome (Sars) epidemic that killed nearly 300 people here in 2003, has sent Mrs Lam's administration scrambling.
In one way, pressuring Mrs Lam has brought conflicting camps together, with even some pro-establishment figures speaking out in recent days to urge her to limit travel to Hong Kong from mainland China.
On Tuesday, she relented. Speaking at a news conference with a mask over her face, she announced the shutdown of major rail passenger links and limits on flights for people coming from the mainland. The government in Beijing will also stop issuing visas for individual travellers to Hong Kong from the mainland.
Those moves were unprecedented, Hong Kong researchers say, and were avoided even during the height of the Sars epidemic.
Many Hong Kong civil servants will work from home for the rest of the week. Officials called for private employers to permit similar working arrangements to keep people off the streets after the end of the Chinese New Year holiday.
More broadly, the concern over the outbreak is again bringing resentment of the mainland to the fore. As they did during the Sars crisis, and then again during the protests against Beijing's intervention in the Hong Kong territory's limited autonomy, people here are expressing distrust over the Chinese leadership's lack of transparency and arbitrary decision-making.
And for many, that distrust is extended to Mrs Lam, Beijing's handpicked chief executive, who will be under even heavier scrutiny as she tries to bring a divided city together to head off the outbreak.
"We learned the lesson from Sars," said Ms Wong Hoi Ying, a district council representative in Fanling, the location of a proposed quarantine site in northern Hong Kong.
"We put on our masks even before the coronavirus was confirmed to have entered Hong Kong."
Ms Wong said she was shocked to learn from a news conference last Saturday that the Hong Kong government had identified the unoccupied public housing complex, in Fanling, as a possible quarantine site for the relatives of infected people.
Her constituents "were outraged", she said. "It's within 100m of residences nearby, there are at least two schools and a few more kindergartens in the vicinity. It's not a suitable location for quarantine purposes."
Within hours of the protest on Sunday, the authorities said they were delaying plans to use the public housing complex, while moving ahead with the use of remote, government-owned vacation bungalows.
On Tuesday, Mrs Lam said the government would abandon any plans to use the Fanling site.
"The militancy of residents caught them by surprise," said Ma Ngok, an associate professor of political science at the Chinese University of Hong Kong. He noted that the protesters included not only the contingent that has been rallying against the government for months, but also some people from the pro-establishment camp known as the blue ribbons.
"They ostensibly support the government, but when it came to using their neighbourhood for quarantine, they came out and blocked the roads," Prof Ma said.
Late Sunday, the government said it would bar residents of Hubei, the province that includes Wuhan, or anyone who had travelled there in the past two weeks from entering Hong Kong.
Just a day earlier, Mrs Lam had resisted calls for keeping out mainland visitors, saying it would be "inappropriate and impractical".
She faced expanded demands to restrict arrivals from the mainland. Some medical workers and epidemiologists, labour unions and even pro-Beijing politicians called for a more complete closure.
On Tuesday, after a suspected explosive device was found in a trash can at a checkpoint at the mainland border, an anonymous message appeared on social media threatening a campaign to damage roads and railways connecting the city to mainland China.
"If the Hong Kong communists refuse to close (the border), we will do it for you," the message said.
Her critics point out that Mrs Lam did not act to stop entries from Hubei until Macau, the former Portuguese colony that like Hong Kong operates with some autonomy from the central government, did it first. Macau said on Sunday that it would allow residents from Hubei to enter only if they provided documentation to show they were not infected.
The heightened restrictions announced on Tuesday might still not be enough, as several border crossings and the airport remain open, Prof Ma said.
"It shows she can respond to public opinion, but it might be too little to late," he said.
Still, in many ways, Hong Kong is the best-equipped Chinese city for dealing with an outbreak.
It was one of the first places in China to begin reporting possible cases of infection from the coronavirus. And it has deep and painfully earned experience from the Sars outbreak, which killed at least eight healthcare workers. Some of the survivors still have lung damage 17 years later.
Doctors and nurses in Hong Kong have drawn lots to determine when they would work in coronavirus isolation wards for six-week shifts, said Dr Arisina Ma, the president of the Public Doctors' Association. One hospital rearranged its cafeteria so that all tables faced the walls, a precaution from the Sars era to help prevent employees from infecting each other during their meals.
The health authorities were scrambling to find living quarters for health workers after they had completed duty inside isolation wards. Hotels were also unwilling to accept large numbers of medical workers for fear of public reaction.
Dr Ma suggested requiring visitors and residents who were returning from the mainland at the close of the Chinese New Year holiday to stay home for 14 days, the incubation period for the disease.