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WASHINGTON, Oct 3 (Reuters) - U.S. Defense Secretary Jim Mattis said on Tuesday the United States should consider staying in the Iran nuclear deal unless it were proven that Tehran was not abiding by the agreement or that it was not in the U.S. national interest to do so.
Although Mattis said he supported U.S. President Donald Trump's review of the agreement curbing Iran's nuclear program, the defense secretary's view was nonetheless far more positive than that of Trump, who has called the deal agreed between Iran and six world powers in 2015 an "embarrassment".
Trump is weighing whether the deal serves U.S. security interests as he faces a mid-October deadline for certifying that Iran is complying with the pact, a decision that could sink an agreement strongly supported by the other powers that negotiated it.
"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," Mattis told a Senate hearing.
"I believe ..., absent indications to the contrary, it is something that the president should consider staying with, Mattis added.
Earlier, when Mattis was asked whether he thought staying in the deal was in the U.S. national security interest, he replied: "Yes, senator, I do."
The White House had no immediate comment on Mattis' remarks, which once again highlighted the range of views on key policy issues within the Trump administration.
If Trump does not recertify by Oct. 15 that Iran is in compliance, Congress would have 60 days to decide whether to reimpose sanctions on Tehran suspended under the accord.
That would let Congress, controlled by Trump's fellow Republicans, effectively decide whether to kill the deal. Although congressional leaders have declined to say whether they would seek to reimpose sanctions, Republican lawmakers were united in their opposition to the deal reached by Democratic former President Barack Obama.
IRAN "FUNDAMENTALLY" IN COMPLIANCE
In a House of Representatives hearing later on Tuesday, Mattis said Iran was "fundamentally" in compliance with the nuclear deal.
"I believe that they fundamentally are. There have been certainly some areas where they were not temporarily in that regard, but overall our intelligence community believes that they have been compliant and the IAEA also says so," Mattis said, using an acronym for the International Atomic Energy Agency.
A collapse of the deal could trigger a regional arms race and worsen Middle East tensions.
Last month, Iran's President Hassan Rouhani said the accord cannot be renegotiated.
Last month, the top U.S. military officer said Iran was complying with the pact and warned that any American decision to walk away from it would make other nations less likely to enter into agreements with the United States.
Marine Corps General Joseph Dunford, Chairman of the Joint Chiefs of Staff, had said previously that Iran was complying with its obligations under the deal, but had increased its activity in other areas.
Trump has said he has made a decision on what to do about the agreement but has not said what he has decided.
The prospect of Washington reneging on the agreement has worried some U.S. partners that helped negotiate it, especially as the world grapples with North Koreas nuclear and ballistic missile development.
The deal was signed by Britain, China, the European Union, France, Germany, Iran, Russia and the United States.
White House national security adviser H.R. McMaster has defended Trump's criticism of the deal, saying it had the "fatal flaw" of a 'sunset clause,' under which some of the deal's restrictions on Iran's nuclear program expire from 2025.
European ambassadors speaking in Washington last week said they would do everything possible to protect companies based in Europe and that continue to do business with Iran, from reimposed U.S. sanctions.
French Ambassador Gerard Araud noted that the other countries that signed the pact had made clear they do not support renegotiating it.
J Street, a liberal pro-Israel group, said Trump did not have legitimate grounds to decertify the deal.
"If he chooses to do so anyway, he will be acting purely based on divisive politics and dangerous ideology, and endangering the security of the U.S. and our allies, Dylan Williams, vice president of government affairs for the group, said in a statement. (Reporting by Idrees Ali and Phil Stewart in Washington; Additional reporting by Steve Holland; Editing by Yara Bayoumy and James Dalgleish)