"They are not living up to the spirit of the agreement, I can tell you that," Trump told reporters at a press conference with Italian Prime Minister Paolo Gentiloni yesterday. "I think they (Iranians) are doing a tremendous disservice to an agreement that was signed. It was a terrible agreement. It shouldn't have been signed."

The US President said his administration was analysing the agreement signed under former president Barack Obama "very, very carefully" and would take a decision on it soon.

"It shouldn't have been negotiated the way it was negotiated. I'm all for agreements, but that was a bad one, as bad as I've ever seen negotiated," he added.

Trump's barbs come a day after Secretary of State Rex Tillerson announced that the US has started a review of the international nuclear agreement with Iran.

Meanwhile, Congressman Ed Royce, Chairman of the House Foreign Affairs Committee said that the US will not allow Iran to mass produce intercontinental ballistic missiles.

"We are not going to allow the Iranians, now that we've already had a deal where (the Obama administration) gave up all the leverage up front in terms of the sanctions, which was billions in relief, to go forward and mass produce ICBMs so that when we are at the end of the agreement...And we lift everything...They...Have a turnkey operation for ICBMs," Royce told CNN in an interview.

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