President Trump said the risk to Americans remained very low, but his bid to ease nerves - and shore up jittery stock markets in an election year - came as officials confirmed the first case of suspected "community transmission" of the COVID-19 disease in the country.
U.S. President Donald Trump, seeking to calm markets and an increasingly anxious public, said in a live broadcast that the United States was "very very ready" to face the virus threat and that Vice President Mike Pence would be in charge of the national response.
Mainland China - where the virus originated late past year - reported 327 new cases on Friday, the lowest since January 23.
French authorities are investigating how the man contracted the virus.
His list includes doubts over China's accuracy in counting cases, criticism over Japan's handling of a cruise ship quarantine at one of its ports, and the comparatively small number of people that US authorities have so far tested.
"If people have been to the affected areas that the Italian government have quarantined then they should self-isolate whether or not they have symptoms".
On the positive side, he said, there's the signal that "when you do containment measure like China is doing, you can actually see a decline in the cases and ultimately it can be contained".
China, the starting point of the Covid-19 outbreak, has recorded a total of 78,632 cases and 2,718 deaths.
"This is a situation of concern, but we must not give in to panic", EU Health Commissioner Stella Kyriakides told reporters in Rome on Wednesday.
The disease is believed to have originated in a market selling wildlife in the central Chinese city of Wuhan late a year ago and has infected about 80,000 people and killed more than 2,700, the vast majority in China.
Countries from Denmark to Spain and Algeria have also reported infections linked to Italy. - Fears of a global coronavirus pandemic deepened on February 24 as new deaths and infections in Europe, the Middle East and Asia triggered more drastic efforts to stop people travelling. It has suffered the most deaths outside China - 26 from 245 reported cases.
"Our message continues to be that this virus has pandemic potential and World Health Organization is providing the tools to help every country to prepare accordingly", the World Health Organization chief said.
Tedros reiterated that this is not a time for fear but instead the "time for taking action now to prevent infections and save lives now". Some 28,500 American troops are deployed in South Korea.
The U.S. confirmed one case of the new coronavirus, or COVID-19, in California Thursday that could not be linked to global travel, suggesting the person contracted the virus within the United States.
The streets of Daegu - which has a population of 2.5 million - have been largely deserted for days, apart from long queues at the few shops with masks for sale.
China quarantined 94 air passengers arriving in Nanjing from Seoul after three people, all Chinese, on the flight were discovered to have fevers on Tuesday.
Iran has emerged as a major hotspot in the region, where 22 people have succumbed to the disease - the biggest death toll outside China.
According to Tedros, the United Nations health agency shipped testing kits to 57 countries and personal protective equipment to 85 countries.
The country has been straining to contain the epidemic since last week when it announced its first two deaths in Qom, a centre for Islamic studies and pilgrims that attracts scholars from all over the world.
Shortly after Trump spoke about USA efforts on the virus, health officials identified what could be the first community spread US case.
Iran's latest figures show the virus has spread to all four corners of the country.
Wall Street reversed earlier gains on Wednesday afternoon and oil prices dropped to their lowest level in over a year, spooked in part by health officials saying dozens of people who had been in China were being monitored in suburbs of populous NY city - although no confirmed cases have been found.