President Donald Trump on Wednesday moved to invoke a federal law that allows the government to marshal the private sector to deal with the coronavirus epidemic, as the economic damage mounted with word that Detroit's Big Three automakers agreed to shut down all their factories to protect workers.

On a day of head-spinning developments, stocks tumbled again on Wall Street. More borders slammed shut across Europe and North America, with the U.S. and Canada agreeing to close their shared boundary to all but essential travel.

And the Trump administration pressed Congress to swiftly pass a potentially $1 trillion rescue package to prop up the economy and speed relief checks to Americans in a matter of weeks.