“Absent indications to the contrary, it is something that the president should consider staying with,” Mattis told members of the Senate Armed Services Committee on Tuesday, The New York Times reported.
"If we can confirm that Iran is living by the agreement, if we can determine that this is in our best interest, then clearly, we should stay with it," he added.
"I believe, at this point in time, absent indications to the contrary, it is something the president should consider staying with."
Last month, Trump, during an address before the United Nations General Assembly, said, "The Iran deal was one of the worst and most one-sided transactions the United States has ever entered into frankly that deal is an embarrassment to the United States, and I don't think you've heard the last of it”.
Iran and the Group 5+1 (Russia, China, the US, Britain, France and Germany) reached the 159-page nuclear agreement in July 2015 and implemented it in January 2016.
Since the historic deal was signed in Vienna, the International Atomic Energy Agency (IAEA) has repeatedly confirmed the Islamic Republic’s compliance with its commitments under the JCPOA, but some other parties, especially the US, have failed to live up to their undertakings.