The third person to have been diagnosed with coronavirus in the UK is believed to have caught the disease in Singapore.
It comes as Japan reported 41 new cases of the illness on a quarantined cruise ship near Yokohama. Before the new cases, 20 infected passengers had been escorted off the Diamond Princess.
Meanwhile, a Chinese doctor who had been threatened by police after sounding the alarm about the coronavirus died.
The illness has killed 636 people and infected 31,161, with 260 cases recorded outside of China.
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Hong Kong has said it may jail or fine anyone who fails to observe the two-week quarantine for arrivals from mainland China, starting on Saturday.
Hong Kong has refused to completely seal its border with mainland China but hopes the quarantine will dissuade cross-border travelers.
It also applies to travelers coming from other countries who had been to mainland China in the past 14 days.
Hong Kong residents will be allowed to quarantine themselves at home while foreigners must stay in hotels or their arranged accommodations. Those without any plans will be sent to quarantine camps.
Those who do not observe the quarantine could face up to six months in jail.
The third person to have been diagnosed with coronavirus in the UK is believed to have caught the illness in Singapore.
The patient is reported to be a middle aged British man, and is understood to be the first UK national to contract the disease.
He is thought to have been diagnosed in Brighton and was transferred St Thomas' Hospital in London, where there is an infectious disease unit, on Thursday afternoon.

Before Friday, 20 infected passengers had been escorted off the Diamond Princess at Yokohama, near Tokyo.
At least four other cruise ships, two foreign and two Japanese-operated, are headed to Japan by the end of the month, transport minister Kazuyoshi Akaba said, urging port authorities around the country to turn them away.

A British passenger on board the Diamond Princess cruise ship is among those who tested positive for coronavirus.
The British man was on his honeymoon and will be separated from his wife, a fellow passenger has said.
David Abel said in a video update posted on Facebook that he had been dining with the man, who was not named.
"He will almost certainly be leaving the ship today - real, real shame. I have no idea how he must be feeling ... they're on their honeymoon.
"He will be going off in to quarantine in a medical facility and she has to stay on board the ship because she's not displaying symptoms.
"That's going to be really, really tough for him so just bear a thought for these passengers who just don't know what is going to be lying ahead of them."

The death of a doctor who was threatened by police after raising an early alarm about the coronavirus has sparked an outcry in China.
Dr Li Wenliang, 34, had worked at a hospital in the epicenter of the outbreak in the central city of Wuhan.
He was one of eight medical professionals in Wuhan who tried to warn colleagues and others when the government did not, writing on his Twitter-like Weibo account that on 3 December he saw a test sample that indicated the presence of a coronavirus similar to Sars, which killed nearly 800 people in a 2002-2003 outbreak that the government initially tried to cover-up.
Dr Li wrote that after he reported seven patients had contracted the virus, he was visited on 3 January by police, who forced him to sign a statement admitting to having spread falsehoods and warning him of punishment if he continued.
A copy of the statement signed by Dr Li and posted online accused him of making "false statements" and "seriously disturbing social order."
"This is a type of illegal behavior!" the statement said.

Dozens more catch coronavirus onboard quarantined cruise ship near Japan
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The deadly coronavirus outbreak could have spread from bats to humans through the illegal trade of pangolins, Chinese researchers have said.
"This latest discovery will be of great significance for the prevention and control of the origin (of the virus)," South China Agricultural University, which led the research, said in a statement on its website.
The outbreak is believed to have started in a market in the city of Wuhan, in central Hubei province that also sold live wild animals. Health experts think it may have originated in bats and then passed to humans, possibly via another species.
The government is urging travellers from countries including Thailand, Singapore, Japan and South Korea to self-isolate if they begin to feel unwell. Other countries on the list are Hong Kong, Taiwan, Japan, Malaysia, South Korea and Macau, as well as mainland China.
Anyone arriving from these locations should stay indoors and avoid contact with other people if they develop symptoms such as a cough, fever or shortness of breath, the advice warns.
The warning, posted on the government website, says: "These countries have been identified because of the volume of air travel from affected areas, understanding of other travel routes and number of reported cases. This list will be kept under review."
Until Thursday, this advice only related to people travelling from Wuhan in China.

Donald Trump has praised China's "great discipline" in tackling the coronavirus outbreak.
Tweeting after a phone conversation with Xi Jinping, China's president, Mr Trump said: "Nothing is easy, but he will be successful, especially as the weather starts to warm & the virus hopefully becomes weaker, and then gone.
"Great discipline is taking place in China, as President Xi strongly leads what will be a very successful operation. We are working closely with China to help!"
Singapore has reported three more coronavirus cases that authorities have not yet linked to previous infections or travel to China, prompting the city state to raise its countrywide alert level.
The new cases take Singapore's the city-state's virus tally to 33 with the alert level raised to orange, denoting the disease is severe and passes easily from person-to-person.

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The world is facing a shortage of personnel protective equipment against coronavirus, according to the World Health OrganisationThailand's health minister has said Western tourists who refuse to wear face masks should be kicked out of the country.
Health officials in the Lazio region, which includes Rome, said the patient has been moved from a military facility to the Spallanzani National Institute for Infectious Diseases in the capital, where two Chinese tourists with the virus are being treated.

China's official news agency has said Xi Jinping urged the US to "respond reasonably" to the virus outbreak in a phone call with Donald Trump.
China's foreign ministry has previously complained the US was flying its citizens out of the worst-hit city of Wuhan but not providing any assistance to China.
The White House said Mr Trump "expressed confidence in China's strength and resilience in confronting the challenge" of the outbreak in his conversation with the Chinese president.
Communist Party newspaper Global Times said Mr Xi told Mr Trump China has "full confidence and capability to overcome" the outbreak and that the "long-term positive trend of the Chinese economy remains unchanged."

The director-general of the World Health Organisation (WHO) has cautioned against reading too much into a two-day drop in the number of new virus cases.
Tedros Adhanom Ghebreyesus spoke during a technical briefing to the UN health agency's executive board, saying: "The numbers could go up again ... but the last two days were showing a declining trend."
Mr Tedros also reported in response to his appeal earlier this week for more countries to share more patient and other information about the outbreaks in their countries, not all countries had provided the requested information.
"There are some countries who have yet to send detailed case reports to WHO," he said. "We urge those member states to share that information immediately."

Death of Chinese doctor who warned about coronavirus sparks outpouring of anger
Under-fire government launches investigation into ‘issues raised by public’Hong Kong has said it may jail or fine anyone who fails to observe the two-week quarantine for arrivals from mainland China, starting on Saturday.
Hong Kong has refused to completely seal its border with mainland China but hopes the quarantine will dissuade cross-border travelers.
It also applies to travelers coming from other countries who had been to mainland China in the past 14 days.
Hong Kong residents will be allowed to quarantine themselves at home while foreigners must stay in hotels or their arranged accommodations. Those without any plans will be sent to quarantine camps.
Those who do not observe the quarantine could face up to six months in jail.

The British passenger on board a cruise ship who tested positive for coronavirus has posted about his plight on social media.
"Would also like to say that at the moment I am not showing any symptoms so just possible a carrier.
"Will let you know how I am going on when possible."
The diagnostic test currently used in London will be rolled out to centres across England, Wales, Scotland and Northern Ireland to increase daily testing capacity and speed up results. A confirmatory test will continue to be conducted at PHE's Colindale laboratory.