President Trump is likely to call for additional sanctions on Iran in the coming days as he approaches a deadline to decide on extending waivers for existing sanctions against the regime, Treasury Secretary Steven Mnuchin said Thursday.

"I am expecting more sanctions on Iran," Mnuchin told reporters at the White House.

Trump faces a deadline this week whether to continue the suspension of sanctions the Obama administration lifted in exchange for the nuclear deal that Trump has long criticized. The president has asked Congress to examine the nuclear agreement, and said last year that he does not believe the deal is in the interest of the U.S.

"I am not going to make any specific comments on that. It is still under discussion," Mnuchin said of Trump's upcoming decision on the sanctions waivers.

But the Treasury secretary repeated Trump's claim that the agreement needs fundamental alterations to remain in place. Trump has been threatening to cancel the agreement since the presidential race.

"Many aspects of the Iran deal need to be changed," Mnuchin said. "There are many activities outside of the Iran deal...that we will continue to sanction."

The Trump administration has said Iran's ballistic missile development and support of groups affiliated with terrorism should factor into the U.S. policy toward Iran more prominently than they did under the Obama administration.

"You can expect there'll be more sanctions coming," Mnuchin said.