Donald Trump has drawn fire for his reference to the coronavirus as a "foreign virus" and for focusing on a ban on European travel despite repeated warnings from health officials that the Covid-19 outbreak's inevitable surge throughout the US is coming through community spread that's already in the country.

In his address to the nation on Wednesday, the president asserted that "the virus will not have a chance against us" as he blamed Europe for failing to contain the outbreak and said the administration's ban on China travel was effective in limiting its spread.

Critics said his focus on closing travel relies on xenophobia and merely shifts the blame as Americans brace for a spike in infections with limited testing capabilities.

The president said: "We are marshalling the full power of the federal government and the private sector to protect the American people. This is the most aggressive and comprehensive effort to confront a foreign virus in modern history."

But there are nearly 1,300 cases in the US, including at least 37 deaths — two weeks after the president announced that the US would be "close to zero" patients within a "couple of days".

Officials in health departments across the US have urged the cancellations of "mass gatherings" and warned of inevitable rise in new cases through community spread with no known source of infection. Health workers have stressed that otherwise "healthy" people who don't appear to be sick may pose a risk as a vector to other people who could be vulnerable to the virus.

In their response to the president's address, Senator Minority Leader Chuck Schumer and House Speaker Nancy Pelosi said: "Alarmingly, the president did not say how the administration will address the lack of coronavirus testing kits throughout the United States."

The "virus is already here" said Congressman Ted Lieu. "What we need is sufficient testing, which we don't have."

Mr Trump's address followed the World Health Organization's declaration of a pandemic, as the virus reaches more than 100 countries with a death toll of more than 4,000.

"This is not about a 'foreign virus', whatever that means," New York Governor Andrew Cuomo told CNN. "It's here. It's community spread. It's much more prevalent than we know ... The numbers of cases are going to skyrocket [and] that is going to be jarring for the American people."

New York has created a "containment" area in New Rochelle, north of New York City in Westchester County, where hundreds of people are under quarantine.

On Wednesday, Dr Anthony Fauci with the National Institutes of Health told Congress that "it is going to get worse" as the president attempted to calm market fears amid historic drops on the Dow Jones. Following a White House briefing later that day, the president dismissed a question about health officials contradicting his claims as "fake news."