The death toll from China's new coronavirus grew to 80 on Monday as residents of Hubei province, where the disease originated, were banned from entering Hong Kong amid global efforts to halt the rapid spread of the outbreak.

The number of deaths from the flu-like virus in Hubei climbed from 56 to 76 overnight, health commission officials said, with four deaths elsewhere in the country. The total number of confirmed cases in China had risen to 2,744.

China's cabinet said it would extend the week-long Lunar New Year holiday by three days to Feb. 2 in a bid to slow the spread of the virus. The Hubei city of Wuhan, the epicentre of the outbreak, is already under virtual lockdown, with severe restrictions on movement in place in several other Chinese cities.

Beijing has called for transparency in managing the crisis, after public trust was eroded by a cover-up of the spread of SARS, a coronavirus that originated in China and killed nearly 800 people globally in 2002 and 2003.

The newly identified coronavirus has created alarm because much about it is still unknown, such as how dangerous it is and how easily it spreads between people. It can cause pneumonia, which has been deadly in some cases.

The virus, believed to have originated in a seafood market in Wuhan that was illegally selling wildlife, has already spread to cities including Beijing and Shanghai.

Global screening

The World Health Organization (WHO) last week stopped short of calling the outbreak a global health emergency, but some health experts question whether China can contain the epidemic.

WHO Director-General Tedros Adhanom Ghebreyesus said on Saturday he was on his way to Beijing to meet officials and health experts dealing with the coronavirus.

"My @WHO colleagues & I would like to understand the latest developments & strengthen our partnership with China in providing further protection against the outbreak," he said on Twitter.

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Chinese-ruled Hong Kong has six confirmed cases and said it would ban entry from Monday to people who have visited Hubei province in the past 14 days. The ban does not apply to Hong Kong residents.

Airports around the world have stepped up screening of passengers from China, although some health officials and experts have questioned the effectiveness of these efforts.

France, Italy, Japan and the United States all said they were working to evacuate citizens from Wuhan.

France said it expected to repatriate up to a few hundred of its 800 citizens living in the Wuhan area. Evacuees would have to spend 14 days in quarantine to avoid spreading the virus in France.

A man wearing a face mask rides a nearly empty subway train in Beijing on Sunday. (Mark Schiefelbein/Associated Press)

Hubei's governor, Wang Xiaodong, said at a news conference on Sunday he felt "agonized" and responsible for the outbreak. He described the situation as severe and said medical supplies were still tight.

News of the press conference sparked anger on Weibo, China's equivalent to Twitter, although social media platforms in China usually delete such sensitive content.

"He thinks one sentence of apology will be enough to solve the problem? Let's await the judgment of the people of the country," one user posted.

'Transmissibility shows signs of increasing'

China's health minister has indicated the ability of a new strain of coronavirus to spread in his country is getting stronger and the number of infections could continue to rise.

Ma Xiaowei spoke Sunday after China released new figures showing the death toll from the virus.

"The transmissibility shows signs of increasing and the 'walking source of infection' [where patients have few signs of disease] has made it difficult to control and prevent the disease.

"For this new coronavirus we have not identified the source of the infection and we are not clear about the risk of its mutation and how it spreads. Since this is a new coronavirus there might be some changes in the coming days and weeks, and the danger it poses to people of different ages is also changing," he said.

The minister declined to estimate how long it would take to bring the situation under control, but said travel restrictions and other strict measures should bring results "at the lowest cost and fastest speed."

U.S. confirms 5th case

The U.S. has five confirmed cases, all among people who travelled to Wuhan, health officials said Sunday.

Two new cases were reported Sunday — one in Los Angeles County in California and the other in Maricopa County, Ariz. The latter case was someone with ties to Arizona State University who did not live in school housing, state health officials said.

The three previously reported cases were a patient in Orange County, California; a man in his 30s in Washington state; and a woman in her 60s from Chicago.

The U.S. patients generally have been reported to be in good condition and were hospitalized in isolation for monitoring.

The U.S. Centers for Disease Control and Prevention expects many more Americans to be diagnosed with the newly discovered virus, which is believed to have an incubation period of about two weeks, as worldwide the number of confirmed cases nears 2,000. The CDC is screening passengers on direct and connecting flights from Wuhan at five major airports in Atlanta, Chicago, New York City, San Francisco and Los Angeles.

CDC officials noted Sunday that more than two dozen people who had been suspected of having the illness ended up testing negative.

In Canada, health officials in Ontario on Saturday confirmed its first "presumptive" case of coronavirus, a man in his 50s who was in Wuhan before flying to Toronto on Jan. 22.