Russian Foreign Minister Sergei Lavrov has told US Secretary of State Rex Tillerson that Iran abides by all its commitments on the Joint Comprehensive Plan of Action (JCPOA), and emphasized that all co-authors of the document must abide by it, the Russian Foreign Ministry said after a telephone conversation of the two diplomats.
Trump will use an executive order to declare Iran's Islamic Revolutionary Guard Corps (IRGC) a terrorist organisation.
Johnson said the agreement - under which Iran agreed to limit its nuclear program in exchange for the lifting of economic sanctions - "was the culmination of 13 years of painstaking diplomacy and has increased security, both in the region and in the UK".
It also would indicate that the United States would be willing to renegotiate agreements with every new administration, giving other countries reason to hesitate on negotiations if they felt future leadership would give them a better deal, Mogherini added.
She said that U.S. would lose global trust "because a deal that America voted for just two years ago in the UN Security Council with a resolution unanimously adopted, a deal that America helped to shape enormously, enormously, would be rejected by the same country".
Senior U.S. officials, European allies and prominent U.S. lawmakers have told Trump that refusing to certify the deal would leave the U.S. isolated, concede the diplomatic high ground to Tehran, and ultimately risk the unraveling of the agreement.
And if that fails, Cotton said, "We may have to impose new, even more coercive, sanctions". However, some members of Congress have expressed a willingness to hold off on sanctions to give Trump time to negotiate a strategy with the Europeans to alter the deal.
While the Trump administration has twice certified Iranian compliance with the deal in notifications to the US Congress under an American law, the White House has indicated that a third verification - due later this week - would not be offered.
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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".
No, the deal will not be invalidated if the administration decertifies it. If he does not certify Iran's compliance to the conditions of the deal than congress will have to re-impose sanctions against Iran within 60 days. He also wants to toughen language on ballistic missiles and inspections.
The other signatories to the JCPOA - the UK, France, Germany, Russia, China and Iran, have said it is not realistic to try to renegotiate its terms. "We may have to array our forces to prepare for. calibrated strikes".
Beyond decertification, there are a number of ways the Trump administration could put pressure on Iran to come back to the negotiating table.
Drafts of two proposals seen by The Associated Press, one from Senate Foreign Relations Committee chairman Bob Corker and one from committee member and harsh deal critic Senator Tom Cotton, would expand the United States certification criteria to include items that are also the province of the UN nuclear watchdog and require the USA intelligence community to determine if Iran is carrying out illicit activity in facilities to which the International Atomic Energy Agency does not have access. But again, none of that is likely since the US would be essentially tearing up the agreement and taking the blame for whatever comes next.
House Democrats met earlier in the day with former secretary of state John Kerry and former energy secretary Ernest Moniz, who were the primary negotiators of the deal made between Iran and six world powers.
What exactly that will look like is still being determined, but it could include greater congressional oversight.