"We will use everything within our power to put additional sanctions on Iran, Syria and North Korea to protect Americans lives," he said. "And I can assure you that’s a big focus of mine and I discussed it with the president."
Mnuchin made the comments in his testimony to the House Ways and Means Committee in connection with his department’s drive to crack down on terrorist financing.
Iran and Syria are on the US list of state sponsors of terrorism, and Washington is considering whether to put North Korea back on the list for the first time since its delisting in October 2008 in light of the killing of Kim Jong Nam, the half-brother of North Korean leader Kim Jong Un, in Malaysia in February.
In his testimony, Mnuchin also said the Treasury Department is reviewing licences for Boeing Co and Airbus to sell aircraft to Iran.
"It is correct that both in the case of Boeing and Airbus, there are licences that will be required and they are under review," he said.