President Donald Trump waived nuclear-related sanctions on Iran on Friday, keeping the US in an international deal governing its nuclear program for the time being.But in doing so, a senior administration official said that Trump would not sign any more such waivers going forward— starting a 120-day clock for negotiations over what the White House describes as a supplemental accord with Europe that will impose new terms on Iran over its future nuclear work.The move creates a deadline on talks over a nuclear deal the European Union says is working, and that it will not touch. Should Trump fail to issue future waivers, European entities and businesses will bear the brunt of secondary sanctions, creating a potential crisis in US-EU relations, in addition to whatever actions Tehran might take in response.The senior official said that Trump seeks a multilateral deal not negotiated with Iran at the table, but with European nations willing to set “triggers” for additional sanctions on Tehran upon the sunset of critical provisions of the 2015 accord.The president is seeking an agreement that “never expires,” and that “denies Iran all paths to a nuclear weapon forever— not for ten years or any other shorter period of time,” the senior official said, referring to controversial “sunset” clauses within the nuclear accord.“I do want to stress also that this would not entail direct negotiations with the Iranians, this would be something the United States works out with our European partners only,” the official added. “It would be an agreement amongst the United States and our European partners to re-impose multilateral sanctions should the Iranians surpass the new triggers that we would lay out.”Trump has come under heavy pressure from European allies to issue the sanctions waiver.The Trump administration also said it hopes for an amendment to congressional legislation that imposes triggers on Iran of its own— and that for the first time characterizes Tehran’s ballistic missile program as “inseparable” from its nuclear work, bringing with it harsh sanctions. The nuclear deal, formally known as the Joint Comprehensive Plan of Action, does not address Iran’s ballistic missile program.The Treasury Department also announced 14 new sanctions designations on Iran, including against entities in its aviation sector, the Iranian Revolutionary Guards Corps cyber units and the head of Iran’s judiciary.Trump in October chose not to certify the country's compliance and warned he might ultimately terminate the accord. He accused Iran of “not living up to the spirit” of the agreement even though the International Atomic Energy Agency says Tehran is complying.In a written statement, Trump said the following: "Today, I am waiving the application of certain nuclear sanctions, but only in order to secure our European allies’ agreement to fix the terrible flaws of the Iran nuclear deal. This is a last chance. In the absence of such an agreement, the United States will not again waive sanctions in order to stay in the Iran nuclear deal. And if at any time I judge that such an agreement is not within reach, I will withdraw from the deal immediately."No one should doubt my word. I said I would not certify the nuclear deal—and I did not. I will also follow through on this pledge. I hereby call on key European countries to join with the United States in fixing significant flaws in the deal, countering Iranian aggression, and supporting the Iranian people. If other nations fail to act during this time, I will terminate our deal with Iran. Those who, for whatever reason, choose not to work with us will be siding with the Iranian regime’s nuclear ambitions, and against the people of Iran and the peaceful nations of the world."