The World Health Organisation (WHO) has raised coronavirus threat to the "highest level" in a "wake-up" call to governments amid reports that the disease has spread to 48 countries.
WHO Executive Director of health emergencies, Mike Ryan, said on Friday, "We are on the highest level of alert or highest level of risk assessment in terms of spread and in terms of impact".
Speaking at a news conference in Geneva, he said that it was a "reality check" and a wakeup call to all governments to get ready to face the threat.
He said, "This virus may be on its way and you need to be ready. You have a duty to your citizens, you have a duty to the world to be ready".
At the UN, Secretary-General Antonio Guterres added a note of caution, "This not a time for panic - it is time to be prepared - fully prepared".
"We know containment is possible, but the window of opportunity is narrowing", he said and called on "all governments to step up and do everything possible to contain the disease - and to do so without stigmatisation, respecting human rights".
WHO Director-General Tedros Adhanom Ghebreyesus said Geneva that the disease should be approached with urgency, but without panic.
"Our greatest enemy right now is not the virus itself. It's fear, rumours and stigma", he said.
He said that WHO had not declared a Coronavirus pandemic because there was no evidence " as yet that the virus is spreading freely in communities".
There has, however, been one case in the United States of a person who had no known contact with anyone suffering from the disease and had not travelled to countries hit by it coming down with coronavirus.
Tedros said that as of Friday morning the disease had spread beyond China to 48 countries, afflicting 4,351 people and causing 67 deaths.
The outbreaks in four European countries and Nigeria have been traced to Italy, he said.
While coronavirus could become a pandemic, Tedros said that "with the right measures, it can be contained".
Ryan said that for it to become a pandemic every person the planet will have to be exposed to it and that is not backed by data now.
He said that China has shown that it can be prevented if actions are taken quickly.