The White House is giving Americans an extra 90 days to pay their tax bills as the coronavirus outbreak affects every aspect of routine life - but the April 15 filing deadline still stands.

Treasury Secretary Steven Mnuchin made the announcement Tuesday as he and Donald Trump laid out the administration's latest steps to stifle the spread of the virus and guard against what many experts are warning will be a massive economic slowdown fuelled by decreased consumer spending and millions of lost jobs.

Mr Mnuchin urged Americans to still file their taxes by the usual mid-April date so they receive any returns in a timely manner. The idea is to give those Americans some extra cash during what could be an extended national lockdown.

"Americans need cash now," he declared.

He urged Americans to file their returns online because that is "easiest" for both taxpayers and the IRS. What's more, he announced the administration will implement a three-month window during which tax payments can be put off.

"If you owe a payment to the IRS, you can defer up to $1m as an individual" for up to 90 days, he told reporters. For corporations, the figure is $10m.

Meantime, as US stock markets rebounded slightly Tuesday after over a week of losses, Mr Mnuchin said the administration has no intention of shuttering the Dow Jones Industrial Average and other indexes to stamp the monetary bleeding.

"We absolutely believe in keeping the markets open, okay? Americans need to know they have access to their money. After September 11, the only reason why the markets were closed was because the technology was disrupted," Mr Mnuchin said.

But he also left open the possibility that the White House "may" be forced to "shorten" the length of the trading day, which now spans 9:30 a.m. to 4 p.m.

"I have been on the phone with the major banks with the New York Stock Exchange. Everybody wants to keep it open," he added. "We may get to a point where we shorten the hours, if that is something they need to do, but Americans should know that we are going to do everything to make sure that they have access to their money at their banks, to the money in their 401(k), and to the money in stocks."

"So I want to just be very clear we intend to keep the markets open," he said, just as the Treasury boss said the administration is intent on allowing citizens to travel within the United States.

"The president wants to make sure that although we don't want people to travel unless it's critical, we want to maintain for critical travel the right to have domestic travel," he said.

Mr Trump soon dismissed Mr Mnuchin so he could return to talks with lawmakers from both parties about what an administration source confirmed earlier Tuesday could be an economic stimulus package as large as $850bn to try staving off a recession because of the national near-shutdown due to the coronavirus.

Senior Democratic and Republican lawmakers are talking about passing such a massive package before week's end. While some details are still being sorted -- like whether to include a provision providing payroll tax relief or one to send around $1,000 to some Americans.