Two members of the same family have tested positive for coronavirus in England.
The first cases of the virus to be diagnosed in the UK were announced as more than 80 Britons on an evacuation flight from the Chinese city at the centre of the outbreak were due to land in the UK.
The Department of Health declined to say where in England the patients are from but it is understood they are not in the Wirral area, where a special facility has been set up to quarantine those returning from Wuhan.
They are being treated at a hospital in Newcastle, sources told the PA news agency.
On Wednesday night, an apartment-hotel in Yorkshire was put on lockdown when a man, understood to be a Chinese national, was taken to hospital after falling ill.
The man, who was a guest at the Staycity Hotel in the centre of York, was taken to hospital, together with family members, by medics.
In a statement on Friday about the first two confirmed UK cases, Chief Medical Officer Professor Chris Whitty said: "The patients are receiving specialist NHS care, and we are using tried and tested infection control procedures to prevent further spread of the virus.
"The NHS is extremely well-prepared and used to managing infections, and we are already working rapidly to identify any contacts the patients had, to prevent further spread.
"We have been preparing for UK cases of novel coronavirus and we have robust infection control measures in place to respond immediately.
"We are continuing to work closely with the World Health Organisation and the international community as the outbreak in China develops to ensure we are ready for all eventualities."
There are four Airborne High Consequences Infectious Disease Centres (HCIDs) in England which are specially equipped to receive people with illnesses such as coronavirus.
These are Guy's and St Thomas' NHS Foundation Trust, Royal Free London NHS Foundation Trust, Royal Liverpool and Broadgreen University Hospitals NHS Trust, and Newcastle upon Tyne Hospitals NHS Foundation Trust.
Another plane to China
It comes as ministers said the Government will send another plane to coronavirus-hit Wuhan to rescue British citizens if needed.
Some people wanting to leave the city said they were unable to board the flight as they did not receive information in time from the Foreign Office.
Families had been told that relatives with Chinese passports would be unable to join them after Chinese officials denied them permission to leave the country.
That decision was reversed hours before the plane was due to depart, but some people did not have time to get to the airport.
PA understands that the Foreign Office is working with EU countries to add British passengers to any rescue flights they may charter back from Wuhan.
After several delays, the evacuation flight left Wuhan at 9.45am local time on Friday, carrying 83 Britons and 27 non-UK nationals, mostly from EU countries.
The flight is expected to arrive at the Brize Norton RAF base in Oxfordshire at around 1pm, the FCO said.
Cabinet Office Minister Michael Gove told Sky News on Friday that another plane will be sent if necessary.
He added: "The flight which is the air at the moment is not the end of our efforts.
"It is only one part that we are doing in order to keep people safe.
"We will do everything we can to ensure that every UK citizen, every UK national, every member of their family is contacted, supported.
"If we need to, we will send another plane."
Briton Adam Bridgeman told BBC Radio 4's Today programme on Friday that he, his Chinese wife and one-month-old son had been unable to get a car to the airport in time to catch the flight.
He said his wife had tried the police, and the Foreign Office had eventually sent a car to take them to the airport.
Mr Bridgeman added: "But unfortunately, by the time he arrived - because we had some trouble getting him to get to the right spot to pick us up - by the time he was there, we only had about 15 minutes to get to the airport, so we thought 'It's too late' so we just went home."
One British teacher, who asked not to be named, said she had stayed behind because her husband was a Chinese national and therefore would not be allowed to join her.
But she claimed she had not been told by the Foreign Office of the change of policy, instead learning of it through messages from other British expats.
The evacuation flight came after the UK's four Chief Medical Officers raised the risk level of the illness from low to moderate and the World Health Organisation (WHO) declared an international public health emergency.
Chinese health officials said on Friday morning that the death toll in the country from the virus had risen to 213, up from 170 a day earlier, with the number of known cases rising from 7,711 to 9,692.
No deaths have occurred outside China, although 82 cases have been confirmed across 18 countries.
The British passengers on the evacuation flight - who have mainly been in Wuhan and the surrounding Hubei province - had to sign a contract agreeing to isolation before they could board the flight, and underwent temperature checks.
On arrival, they will be taken by bus to Arrowe Park Hospital on the Wirral for a quarantine period of 14 days, where they will be housed in an NHS staff accommodation block with access to the internet.
Anyone with suspicious symptoms will be taken to the Royal Liverpool and Broadgreen Hospital.