More than a dozen people in the UK have been tested for the new strain of coronavirus, Public Health England has said.
Five people have tested negative while nine others are waiting for results.
In Scotland, where five people were tested, an incident team has been set up to deal with the health threat.
Globally, there are more than 800 confirmed cases of the virus, which has killed 25 people in China. Authorities there are battling to contain it.
PHE’s announcement that 14 people in the UK had been tested came on Thursday night, but they did not give details of where the cases were.
Earlier, the Scottish government confirmed that five people had been tested. Four of them were believed to be Chinese, Downing Street said.
Meanwhile, one man was treated in Belfast for symptoms associated with coronavirus.
All the patients had been in Wuhan – the Chinese city where the virus first broke out – in the last 14 days.
Prime Minister Boris Johnson’s spokesman said the tests were “purely precautionary”.
Health Secretary Matt Hancock said there was an “increased likelihood” of cases of the new coronavirus occurring in the UK, but “we are well prepared” to deal with them.
In a statement to the House of Commons, Mr Hancock said that it was a “rapidly developing situation and the number of deaths and the number of cases is likely to be higher than those that have been confirmed so far and I expect them to rise further”.
He told MPs: “The chief medical officer has revised the risk to the UK population from ‘very low’ to ‘low’ and has concluded that while there is an increased likelihood that cases may arise in this country, we are well prepared and well equipped to deal with them.”
He added: “The UK is one of the first countries to have developed a world-leading test for the new coronavirus.”
Wuhan – which has a population of 11 million people – has gone into lockdown, with authorities suspending planes and trains in and out of the city.
Beijing, Hong Kong and Macau have also cancelled some major festivities to prevent large crowds gathering together, as the country prepares to celebrate the Lunar New Year.
On Thursday, Vietnam and Singapore joined the list of countries where the virus had spread. Cases have also been reported in Thailand, the US, Taiwan, Japan and South Korea.
Authorities around the world have announced screening measures for passengers from China.
In response to the outbreak, the Foreign Office has advised against all but essential travel to Wuhan.
The UK is monitoring direct flights arriving from China as a precaution.
Passengers are receiving leaflets and advice on what to do if they fall ill, and a health team is available at Heathrow Airport to check for symptoms.
The World Health Organization has declined to designate the virus an “international emergency”, but the WHO’s director general said: “”It may yet become one.”
Peter Piot, professor of global health and director of the London School of Hygiene & Tropical Medicine, said: “The good news is that the data to date suggests that this virus may have a lower mortality than Sars, we have a diagnostic test and there is greater transparency than decades gone by.
“And that is essential because you cannot deal with a potential pandemic in one country alone.”
What do we know about the virus?
Currently known as 2019-nCoV, the virus is understood to be a new strain of coronavirus not previously identified in humans.
The Sars (Severe Acute Respiratory Syndrome) virus that killed nearly 800 people globally in the early 2000s was also a coronavirus, as is the common cold.
The first human cases were identified in the Chinese city of Wuhan in December 2019. There have not been any other suspected human cases reported prior to this.
Authorities have said it originated in a seafood market that “conducted illegal transactions of wild animals”.
The market has been shut down since the beginning of the year.
The incubation period (how long it takes for symptoms to appear after catching the infection) is days, rather than weeks.
At the moment, there is no vaccine that can protect people against it, but researchers are looking to develop one.