In Wuhan, the epicentre of the outbreak with at least 444 confirmed cases, hospitals, universities and charities appealed for donations of much-needed protective equipment, including face masks, caps and gloves. The city’s health commission also appealed for volunteers to help deliver supplies to hospitals.

Sichuan province was sending 130 health workers to Wuhan, according to People’s Daily.

Medical personnel in the city told the South China Morning Post that there were dire shortages of medical supplies. “We are short of everything, from face masks to goggles,” said a doctor who declined to be named.

There were also runs on food and other necessities in the city, with the price of some staples on the rise.

“A cabbage now costs 35 yuan (US$5), several times more than before the crisis,” Wuhan resident Alex Wang said. “Stocks of some supermarkets with online delivery services have run out.

“The shopping malls, main roads and restaurants that are usually busiest are now so empty. The roads are also empty, even during peak traffic hours. It’s like a ghost town.”

Chinese pharmaceutical firms were ramping up production of surgical masks in response to mass panic buying of medical protective gear nationwide, Hubei Daily reported.

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Authorities were also racing to convert regular hospital wards into isolation wards to cope with the influx of patients, one person working on the conversions said.

At the same time, the city government was aiming to build a temporary hospital with prefabricated materials in six days, online news portal Jiemian reported. The report said the facility would be similar to one built in Beijing during the severe acute respiratory syndrome, or Sars, outbreak 17 years but did not say how many people it would accommodate.

Under the new restrictions, all public transport in and out of Wuhan, including trains, buses and ferries, stopped at 10am. In the following hours, transportation out of seven other cities in Hubei province – Huanggang, Ezhou, Chibi, Xiantao, Qianjiang, Zhijiang, and Lichuan – was stopped, according to notices released by relevant local governments.

People in these cities were ordered not to leave unless in exceptional circumstances.

After the announcement on Wednesday night Wuhan residents rushed to railway stations and the airport. Wuhan railway station was packed with passengers at 7am on Thursday before stations closed.

Zhang, a 61-year-old resident, said he was going to Tianjin on a business trip and planned to return on Friday. He said he was afraid of spreading the virus and thought the authorities should have taken preventive measures earlier.

“The Wuhan government said they started using temperature screening equipment last week, but when I went through the entrance, I didn’t see any of those,” he said. “No one checked my temperature.”

A resident surnamed Ding who was driving out of Wuhan said the outbound lanes were jammed, with very few vehicles heading into the city.

“Many want to leave,” he said. “There are doctors screening each car, checking the temperature of all passengers. People are allowed to leave, but the traffic is moving slowly because of the screenings.”

In the southern province of Guangdong, health authorities called all travellers from Wuhan to avoid crowded places and report to hospitals immediately if they developed flu symptoms.

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John Mackenzie, an infectious diseases expert at Curtin University in Australia, said the lockdown in Wuhan may be helpful in containing the disease but might be “already too late” as a preventive measure.

“It’s a good time to try to put a lid on some of the transmission, particularly with Chinese New Year coming up,” Mackenzie said. “It’s probably not a bad move, but whether it’s too late or not is arguable. The whole episode is growing more rapidly than anyone had expected.”

Lawrence Gostin, professor of public health law at Georgetown University, said he was highly sceptical about the city lockdowns.

“First, it can’t be enforced without major human rights violations. Second, there is no evidence that travel bans work. Third, if we congregate 11 million people together in a major city it will cause cross-infection, fear and panic,” Gostin said.

Beijing-based magazine Caixin quoted Guan Yi, director of the State Key Laboratory of Emerging Infectious Diseases at Hong Kong University, as saying that authorities in Wuhan had missed their best opportunity to contain the spread of the disease because people started leaving the city a couple of days ago.

But Zhou Zijun, a professor at Peking University’s School of Public Health, said it was difficult for the central government to justify closing a major city unless the outbreak was serious.

“We have not yet seen evidence of a massive outbreak among people sharing a train or flight. The cases so far have come as a result of close contact with those in Wuhan,” Zhou said.

“If a lockdown came at the end of last year or early this month, many would have rejected it because there was no massive outbreak yet.”

Epidemiologist Ian Lipkin of Columbia University said it would take some time to see if the outbreak would taper out after the quarantine.

“We’ll see whether or not the numbers flatten out, or whether they continue to accelerate … It takes time to really see whether or not it’s tapering out.”

Other big cities also announced measures to try to contain the outbreak. The Forbidden City in Beijing said it would close until further notice and temple fairs to celebrate the Lunar New Year have been cancelled in the capital.

The European Centre for Disease Prevention and Control said the chance of the coronavirus spreading further around the world was high.

If the WHO does declare the Wuhan outbreak an international emergency, it would set off a chain of responses such as travel bans from other countries.

The WHO said that so far “not enough is known to draw definitive conclusions about how [the coronavirus] is transmitted, clinical features of the disease, its severity, the extent to which it has spread or its source”.

“The government of China’s response has so far been comprehensive. The Chinese government is sharing information regularly and working closely with the WHO,” it said.

The WHO has declared five international health emergencies in the past, including the cases of H1N1 swine flu and Ebola.

Josephine Ma, William Zheng, Laurie Chen, Mimi Lau, Sarah Zheng, Wendy Wu and Gigi Choy