On the sidelines of her visit to Washington, EU Foreign Policy Chief Federica Mogherini said the Iran nuclear deal is not open for renegotiation and that US lawmakers have indicated that their goal, as they amend legislation related to the pact, is to keep the US in compliance with the multilateral agreement. The EUs top diplomat pushed back against a common criticism from US opponents of the deal who argue that so-called "sunset" provisions mean that Iran will eventually be able to resume its work toward a nuclear weapon. The sun doesnt set when it comes to nuclear commitments," Mogherini told reporters in a press conference on Tuesday. "Article three says Iran will never develop a nuclear weapon." "The agreement is composed of different provisions, some of them have different durations, but the commitment not to develop nuclear weapons are forever," she said. “The deal is made to stand the test of time, and it does not have a formal end date. It has phased implementation over 10, 15 and 25 years, but at its core is Iran’s commitment to renounce its ambition to develop nuclear weapons forever,” she added. Mogherini pointed out that the European Union wants to avoid the issuance of any US legislation leading to violation of the historic agreement, and she stressed that there is ongoing work and discussions between Brussels and Washington on this issue. “It took us 12 years to agree on extremely dense and complex technical details in a process that required all outstanding issues to be tackled in parallel. Unilaterally reopening discussions on this or that paragraph is simply impossible,” she stressed. “This is a matter of principles and credibility, she added, noting that the Iran deal is endorsed by a resolution of the United Nations Security Council, and “we — both in Europe and in the USA — have always believed in the universal respect of international norms as a fundamental pillar of the international system”.