By Kevin Liptak and Donna Borak, CNN

(CNN) -- Treasury Secretary Steven Mnuchin said on Monday that his decision to delay the introduction of a planned $20 note featuring the portrait of Harriet Tubman was not politically motivated.

"This is a non-political situation where the primary objective of changing the currency is to stop counterfeiting," Mnuchin said during a briefing about cryptocurrencies. He described the delay of the Tubman note, first unveiled with great fanfare by his predecessor Jack Lew, as one due to technology rather than personal preference.

"These are very complex things that once they're developed require different machinery to be made," Mnuchin added. He said there is no scenario in which Tubman notes would be released before the end of a potential second Trump term.

The Washington Post reported on Monday that three current or former government officials appointed by President Barack Obama and involved in the redesign said that Mnuchin has followed a timeline set under the Obama administration.

The push to replace slave-owning President Andrew Jackson with the Underground Railroad hero came in 2016, near the end of Obama's second term.

The Treasury Department's inspector general said in June it would review the Trump administration's decision to delay the release following a request by Senate Democratic Leader Chuck Schumer.

The Tubman bill was expected to be released in 2020 as part of an initiative by the Obama administration. But Mnuchin has repeatedly said such plans would likely be postponed until 2026.

Mnuchin has said he will focus first on the $10 and $50 bills. He would later consider a new redesign of the notes.

President Donald Trump has slammed the redesign as "pure political correctness." As President, Trump visited Jackson's grave and put a portrait of the 19th century populist in the Oval Office.

He also said that Tubman was "fantastic" and suggested putting her on the $2 bill, which features President Thomas Jefferson, instead.