Treasury Secretary Steven Mnuchin warned Republican senators Tuesday that the coronavirus pandemic could drive up US unemployment to 20%, a Republican Senate source told CNN.

Mnuchin's comments came as he urged Republican senators to act on economic stimulus measures totaling $1 trillion designed to avert that kind of worst case scenario.

In the same meeting, Mnuchin also said he is concerned the economic ramifications of the coronavirus pandemic could be worse than the 2008 financial crisis, the source said.

Mnuchin's comments, which were first reported by Bloomberg News, come amid a rising sense of urgency at the White House and on Capitol Hill to confront the increasingly serious threat of the coronavirus pandemic — on both the public health and economic fronts.

Watch: Mnuchin says this is not the time to worry about the deficit