Britain has a "battle plan" to tackle coronavirus, including bringing retired doctors back to work, as three more cases were confirmed in the UK.
Boris Johnson will chair his first COBRA meeting on Monday and has ordered a "war room" to be convened in the Cabinet Office.
It will feature a cross-Whitehall team of communications experts and scientists ahead of a refreshed public information campaign.
The total number of cases in the UK is now at 23, after a teacher in Berkshire tested positive for COVID-19, as well as a person in Gloucestershire, and another from Hertfordshire.
Chief medical officer Professor Chris Whitty said two of the three new patients had recently travelled back from Italy while the other had returned from Asia.
One of them is a staff member at Willow Bank Infant School in Woodley, Berkshire.
In an email, headteacher Michelle Masters urged parents to "remain calm and follow the recommended hygiene procedures".
"The school will be shut for some days to allow for a deep clean and to ensure that the risk of infection remain(s) low," Ms Masters said.
Burford (Day & Boarding) School in the Cotswolds, Oxfordshire, closed on Wednesday after a pupil returned from a holiday in northern Italy and began to feel unwell.
Headteacher Kathy Haig said the decision to shut the school was taken as a "precautionary measure of having the whole school deep cleaned", adding the premises would reopen on Monday.
Health officials are also continuing to establish how a patient in Surrey became the first to catch the illness within the UK.
Haslemere Health Centre was closed on Friday to be cleaned.
It is not known whether the person caught the virus from someone who had been abroad, or if it was a case of 'community spread'.
It is understood new emergency powers will be brought in to give schools, councils and other parts of the public sector powers to suspend laws - including health and safety measures - to cope with a pandemic.
The battle plan says the following could happen:
The government is also considering whether to encourage more home working and discourage unnecessary travel.
The strategy is based on its existing contingency plans for responding to a flu pandemic, but has been adapted to take into account the differences with COVID-19.
The prime minister said the outbreak "may very well be a challenge in the weeks and months ahead", but he is confident "with the help of the NHS and its incomparable staff, this country will get through it - and beat it".
Health Secretary Matt Hancock told Sky's Sophy Ridge on Sunday programme the focus is still to "contain" and "stop the spread here in the UK", and that everyone should continue to "go about their ordinary business" for the time being.
The risk to the public has been raised from low to moderate, but the risk to individuals is said to remain low.
Worst-case-scenario plans show 80% of the population could contract the virus, with up to 500,000 deaths.
Cemeteries and crematoriums have been told to make sure plans are in place to deal with a pandemic.
Fears over coronavirus have sparked a rush on items such as hand gel - and as a result, products usually dispatched within a few days on Amazon are instead being pitched with a delivery date of between several weeks to over a month.
Supermarket Tesco has sold out of most of its range of anti-bacterial hand sanitisers online.
Health officials in Scotland are to begin testing people with flu-like symptoms for coronavirus, even if they have not visited affected areas.
NHS Lothian has introduced a "drive-through" testing centre at the Western General Hospital in Edinburgh. It is for some patients who have been assessed by a specialist team and who have an appointment so they can be tested for the virus in their cars.
On Friday, a British man who was on board a quarantined cruise ship in Japan became the first UK fatality of the coronavirus.
The Foreign Office is advising against travel to China, South Korea, Iran and affected areas in northern Italy - locations where the epidemic is most severe.
Public Health England has concluded more than 10,000 tests so far, and all but 23 have been negative.
Expert teams are actively tracing those who have come into contact with a suspected case.
The government has said unless an individual has been contacted already, or has travelled to an affected area, they should be reassured it is not necessary for them to take any further action.
In other global developments: