Instead, the president urged Congress to consider reimposing sanctions if Iran crosses certain lines, such as firing ballistic missiles or financing terrorism. His decision, which followed what the administration said was a major review of the international deal, could put its future in jeopardy.
Trump said he would not certify that Iran was in compliance with the 2015 deal that blocked its
"We cannot and will not make this certification," Trump said in a speech from the White House ahead of the next deadline for certification on Sunday.
If Congress, as well as the other five major powers that are signatories to the deal, doesn’t take steps to satisfactorily improve it, Trump said, the United States will end its participation in the accord. Besides Iran and the United States, the parties to the agreement are Britain, France, Germany, Russia, China and the
"The longer we ignore a threat, the more dangerous it becomes," Trump said. He called the government in Tehran a "rogue" and "fanatical regime" that has "spread chaos" around the world, and added, "The regime remains the world's leading state sponsor of terrorism."
Iran also violently represses its own citizens and fuels "vicious" civil wars in countries including Yemen and Syria, Trump said.
The nuclear deal, however, was limited by the allies' consensus to addressing the arms threat, not other Iranian activities.
Trump also complained that if the Obama administration had not entered into the deal, which gave Iran relief from sanctions in return for shuttering its nuclear program, Tehran's economy would have collapsed.
Now, he said, "we will deny the regime all paths to a nuclear weapon."
Trump’s statement that Iran was not in compliance contradicts the opinion not only of most world authorities — notably the United Nations watchdog, the
The president's action threatened to further isolate Washington from its key allies and to give a boost to Iranian hard-liners who have opposed the deal from the start, like many American conservatives have. If Congress decides to reimpose the nuclear-related sanctions, a prospect far from clear, the U.S. will in effect withdraw from the agreement.
European allies had been lobbying the Trump administration not to abandon the nuclear deal; while they were chagrined by the decision, there was relief that the president did not "rip up" the accord as he'd vowed since his election campaign.
The European Union's foreign policy chief, Federica Mogherini, said in Brussels, "It is not up to any single country to terminate" the accord. "We have [a] collective responsibility to protect a nuke deal that's working," she added.
Britain, France and Germany issued a joint statement to express their concern with the American action. "We stand committed to the [Iran agreement] and its full implementation by all sides," they said.
Trump instructed the Treasury Department to declare Iran's Islamic Revolutionary Guard Corps a terrorist organization, saying it had provided weapons, money and fighters to numerous militant groups such as Hezbollah in Lebanon and Hamas in the Gaza Strip.
The Treasury order is designed to squeeze Iranian construction, telecommunications and energy industries that have links to the Revolutionary Guard. The administration is hoping the actions will pressure European companies to follow suit.
Iran quickly lashed out, rallying around the Revolutionary Guard and saying any insult to the corps is "an insult to the entire ruling establishment."
"If the IRGC had not taken effective measures, terrorism would have overwhelmed many countries in the region," the Iranian military said in an statement.
In 2015, the Obama administration brokered the agreement with Iran and the six powers after prolonged and hard-fought negotiations. Iran got rid of most of its centrifuges, disabled its plutonium-producing heavy-water reactor at Arak and agreed to regular United Nations inspections. In exchange it received considerable sanctions relief: readmittance to the international banking system, permission to trade on the oil market and the unfreezing of billions of dollars in overseas assets.
Trump and senior members of his administration have repeatedly said that Iran’s broader behavior should be taken into consideration, not merely its agreement to halt efforts to produce nuclear weapons. That would include actions such as Iran’s work to develop ballistic missiles and its support for armed militants in Yemen, Syria and other countries — issues that were never part of the
Now that Trump has punted the matter to Congress, he and senior administration officials are letting lawmakers know what they would like to see in legislation. Tillerson said the administration wants to add amendments that would "lay alongside" the nuclear deal; those would end so-called sunset clauses, which are the dates when some of the curbs on Iran's nuclear program would be lifted.
"We are never going to accept [Iran] resuming their nuclear weapons program," Tillerson said.
He said the administration's strategy would aim to set in stone the constraints on Iran, which contends that it never sought to develop nuclear weapons. It comes at a time when tensions are at a fever pitch with North Korea over its ongoing and more advanced nuclear program.
The secretary of State dismissed suggestions that the administration, by attempting to change the Iranian deal, would erode trust among other nations in Washington's reliability for negotiating any future deals, including with North Korea — as some allies have warned.
"They can trust we will never do a deal this weak again," Tillerson said.
In Washington, the president's decision didn't please the right or the left.
"Our allies and adversaries alike will see this as a signal that the United States doesn't live up to our commitments, making the United States a source of uncertainty instead of a force for solving serious problems."
Several conservative experts said Trump did not go far enough.
"Simply dumping the nuclear agreement in Congress's lap may be the worst possible option," said Danielle Pletka, senior vice president at the conservative American Enterprise Institute. "That would be politically easy, but it won't get the job done."
Trump's national security advisor, H.R. McMaster, said he was confident that Congress, which has failed to pass any major legislation this year, would support amendments that toughen the deal. This is one issue, he said, that has strong bipartisan support.
"No one is for Iran getting a nuclear weapon," McMaster said. "No one is for Iran continuing its destabilizing behavior."
Tillerson was less certain: "I don't want to suggest to you that this is a slam dunk."
For more on international affairs, follow @TracyKWilkinson on Twitter
2:10 p.m.: This article was updated with additional details and reactions.