The projections were grim: Even if the U.S. were to continue to do what it was doing, the coronavirus could leave 100,000 to 200,000 people dead and millions infected. And the totals would be far worse if the nation reopened.

Prime Minister Justin Trudeau said he was proud of Canada's response to the virus amid early signs that the country's caseload was on a different trajectory than the United States, which topped 156,000 cases by midday.

Mexico and the U.S. announced Friday that they would prohibit all "non-essential'' travel across their shared border as part of efforts to control the spread of the coronavirus.

“The Department of State advises U.S. citizens to avoid all international travel due to the global impact of COVID-19,” it said in the new advice.

Trump confirmed he would invoke a statute allowing the surgeon general to block people or goods from certain countries or places to prevent the spread of communicable diseases.

"That guy screwed the pooch... which, by the way, is another way the virus can spread," joked the 'Late Show' host.

Trump has now had multiple direct and indirect contacts with people who have since tested positive for the virus, including three people he spent time with last weekend at his Mar-a-Lago club in Florida.

The announcement was made by U.S. Vice President Mike Pence, who appeared at a Saturday afternoon press conference with U.S. President Donald Trump.

People in both parties say a recession and rampant disease outbreak would cripple Trump's reelection and Republican efforts to capture House control and defend their Senate majority. That's an edge Democrats are primed to exploit.

They rejected Trump's suggestion that Europe is not doing enough to combat COVID-19, saying that the 27-nation bloc "is taking strong action to limit the spread of the virus.''