China's death toll from a new virus increased to 304 on Sunday amid warnings from the World Health Organization that other countries need to be prepared in the event the disease spreads among their populations.

Meanwhile, six officials in the city of Huanggang — neighbouring the epicentre of Wuhan in Hubei province — have been fired over "poor performance" in handling the outbreak, the official Xinhua News Agency reported.

It cited the mayor as saying the city's "capabilities to treat the patients remained inadequate and there is a severe shortage in medical supplies such as protective suits and medical masks."

Figures from the National Health Commission showed an increase of 45 in the death toll and 2,590 in the number of cases for a total of 14,380, well above the number of those infected in in the 2002-03 outbreak of SARS, or severe acute respiratory syndrome, which broke out in southern China before spreading worldwide.

Despite imposing drastic travel restrictions at home, China has chafed at those imposed by foreign governments, criticizing Washington's order barring entry to most non-citizens who visited China in the past two weeks.

Australian Prime Minister Scott Morrison announced similar measures Saturday, following Japan and Singapore.

Medical personnel work around an ambulance plane commissioned from the military at the airport in Ankara, Turkey, on Saturday shortly after it landed after flying from Wuhan, China. (Huseyin Avci/Turkish Ministry of Health via AP)

South Korea and India flew hundreds of their citizens out of Wuhan, the city at the centre of an area where some 50 million people are prevented from leaving in a sweeping anti-virus effort. The evacuees went into a two-week quarantine. Indonesia also sent a plane.

The virus' rapid spread in two months prompted the World Health Organization on Thursday to declare it a global emergency.

That declaration "flipped the switch" from a cautious attitude to recommending governments prepare for the possibility the virus might spread, said the WHO representative in Beijing, Gauden Galea. Most cases reported so far have been people who visited China or their family members.

The agency acted out of concern for poorer countries that might not be equipped to respond, said Galea. Such a declaration calls for a coordinated international response and can bring more money and resources.

WHO said it was especially concerned that some cases abroad involved human-to-human transmission.

"Countries need to get ready for possible importation in order to identify cases as early as possible and in order to be ready for a domestic outbreak control, if that happens," Galea told The Associated Press.

Watch: Construction of two coronavirus hospitals in China nears completion

Time-lapse video released on Friday shows one of two hospitals being built in the city of Wuhan, due to open on Monday. 1:43

The United States declared a public health emergency on Friday and President Donald Trump signed an order barring entry to foreign nationals who visited China within the last 14 days, which scientists say is the virus' longest incubation period. The restrictions don't apply to immediate family of American citizens and permanent residents.

China criticized the U.S. controls and "unfriendly comments" alleging that Beijing was failing to co-operate.

"Just as the WHO recommended against travel restrictions, the U.S. rushed to go in the opposite way. Certainly not a gesture of goodwill," said foreign ministry spokesperson Hua Chunying.

Hospital staff wear face protection at the Princess Margaret Hospital in Hong Kong on Saturday. (Achmad Ibrahim/Associated Press)

Australia, Germany, Japan, South Korea, the United Arab Emirates, the United States and Vietnam all reported new cases Saturday. Spain confirmed its first case — a German man who had close contact with an infected person in Germany and then traveled to the Canary Islands with friends. Four friends who were hospitalized with him have not shown symptoms.

Both the new virus and SARS are from the coronavirus family, which also includes those that cause the common cold.

The death rate in China is falling, but the number of confirmed cases will keep growing because thousands of specimens from suspected cases have yet to be tested, WHO's Galea said.

"The case fatality ratio is settling out at a much lower level than we were reporting three, now four, weeks ago," he said.

Although scientists expect to see limited transmission of the virus between people with family or other close contacts, they are concerned about cases of infection spreading to people who might have less exposure.

Canada has four confirmed cases of cornavirus. The Public Health Agency of Canada, which is working alongside provinces and territories to monitor the novel coronavirus, says the risk to Canadians is low.

Watch: What we actually know about the coronavirus