China is imposing tougher and more wide-ranging measures to contain the accelerating spread of the Wuhan virus outbreak, including banning Chinese tour groups from leaving the country.
The rate of infection has jumped tenfold in just six days, with the death toll at 56 in China, and more than 2,000 people infected globally.
Nearly 20 cities in Hubei province have also been placed under full or partial lockdown by the authorities, affecting more than 50 million people.
The outbreak, which started last month in the Chinese central city of Wuhan, has spiralled into a national crisis, with President Xi Jinping describing it as a "grave situation".
In a meeting with the country's top leaders on Saturday, he directed officials to make dealing with the epidemic their top priority.
"Life is of paramount importance," he said. "When an epidemic breaks out, a command is issued. It is our responsibility to prevent and control it."
Alongside the outbound tour suspension, which begins today, the authorities have also announced a ban on wildlife trading "until the national epidemic situation is over".
The virus is believed to have originated from a wild animal sold illegally at a market in Wuhan.
Yesterday, an epidemic response committee led by Chinese Premier Li Keqiang said it will extend the Chinese New Year holiday beyond Jan 30 to keep the spread of the respiratory disease in check.
Beijing has already delayed the reopening of schools until the middle of next month, while the manufacturing hub of Suzhou prohibited large businesses from reopening earlier than on Feb 8.
Reinforcements have poured into Wuhan, after hospitals were overwhelmed with patients and supplies ran acutely low.
The National Health Commission over the weekend sent 1,230 medical experts and workers from various provinces, and 450 army medics to the city to help with the treatment of patients.
Its minister Ma Xiaowei said yesterday that the virus is infectious during the incubation period of one to 14 days, which was not the case with severe acute respiratory syndrome. Sars was a coronavirus that originated in China and killed nearly 800 people globally in 2002 and 2003.
"According to recent clinical information, the virus' ability to spread seems to be getting somewhat stronger," he told a packed media briefing.
"There are signs that the transmission rate is increasing, and that makes it difficult to control and prevent. We haven't identified the source and we are not clear about the risks of its mutation," Mr Ma said.
Wuhan Mayor Zhou Xianwang also told a press conference late yesterday that he expected an increase of 1,000 more cases in the coming days in Wuhan.
China's Centre for Disease Control and Prevention said yesterday that it is starting work on developing a vaccine, while Beijing's municipal health commission said separately that it has been using anti-HIV drugs to treat infected patients in the capital city.
The outbreak has led to cancellations of large-scale events across the country and the closure of tourist attractions from Beijing's Palace Museum to Shanghai's Disneyland.
China may also be forced to postpone the annual joint session of Parliament and its advisory body in early March if the epidemic is not contained by the end of next month, a source with ties to the leadership told The Straits Times, requesting anonymity.
Meanwhile, the Hong Kong government said last night that it is banning residents of Hubei or anyone who has visited the province in the past 14 days from the territory from today. This does not apply to Hong Kong residents.
The city has been under pressure to close its border with the mainland after it identified at least six cases of infection.
- Additional reporting by Benjamin Kang Lim