Secretary of Defense James Mattis on Wednesday said Washington pulled out of the Iran deal because it was inadequate for the long-term.

Axar.az reports quoting Turkish media.

Speaking at a Senate Armed Services Committee hearing on Defense Department budget, Mattis accompanied by U.S. Joint Chiefs of Staff Chairman Gen. Joseph Dunford, also claimed that the decision of walking away from the deal was taken in over a year.

"So I think we now have the opportunity to move forward to address those shortcomings and make it more compelling. So that effort is underway already with secretary of state, secretary of treasury, and others working the issue," he said.

Backing President Donald Trump's decision, he noted that the U.S. continues working with its allies and will try to lure Iran into more responsible behavior.

"The ballistic missile efforts they [Iran] have, cyberattacks they have been conducting, and the threats to international commerce whether it be out of the Red Sea where we have seen it most recently or backup in the Persian Gulf where it has relented over the last several months," Mattis enumerated, addressing all of what he described as the threats that Iran constitutes.

Also blaming Tehran for Bashar al-Assad's crime in Syria, he said Iran continues its malign activities in Syria and across the region including in Yemen, Bahrain, Saudi Arabia, and Lebanon.

"We have not seen any drawdown or reduction in Iran's malicious activities and malign activities across the region," he added.

When asked whether the U.S. would launch a unilateral attack if Iran returned to its nuclear weapon program, Mattis described the question as a "hypothetical scenario", adding that Washington will pursue the diplomatic path in order to persuade Iran.

Turning to a question on whether the Pentagon is prepared for Iranian threats following the U.S. withdrawal from the nuclear deal, he stated that the current plans are adequate and up-to-date.

Recalling his previous remarks on remaining in the deal, a senator asked Dunford whether his opinion about the deal was still valid.

"My job is really to support the policy. So the president has changed the policy," Dunford responded, adding: "And so my job now is to adjust to that reality and make sure that I am supporting the president’s policy."

Both Mattis and Dunford in previous hearings at the Senate argued that staying in the nuclear deal was in the U.S. national interest.

However, both have immediately changed their views as Trump on Tuesday issued a decision on withdrawing from the internationally-brokered Joint Comprehensive Plan of Action (JCPOA).