Treasury Secretary Steve Mnuchin put Harriet Tubman's role on the $20 bill in question.

The idea of putting the former slave and abolitionist on the bill was proposed during the Obama administration.

Mnuchin told CNBC on Thursday: "Ultimately we will be looking at this issue. It's not something I'm focused on at the moment."

Instead, he said he was concentrating on making sure any tweaks to U.S. currency bills thwart counterfeiters.

"The No. 1 issue why we change the currency is to stop counterfeiting. So the issues of what we change will be primarily related to what we need to do for security purposes. I've received classified briefings on that. And that's what I'm focused on for the most part," Mnuchin said.

"People have been on the bills for a long period of time. And this is something we will consider. Right now, we've got a lot more important issues to focus on," he added.



Jack Lew, secretary of the Treasury under President Barack Obama, last year proposed putting Tubman on the $20 bill, replacing Andrew Jackson, the slave-owning seventh U.S. president.