The U.N.'s nuclear watchdog called attention Tuesday to a 2015 report by its director that said it had "no credible indications" of Iranian activity linked to the development of nuclear weapons after 2009.
The report presented by International Atomic Energy Agency chief Yukiya Amano ended a more than decade-long investigation into allegations Iran worked to develop nuclear arms, which Iran repeatedly denied.
Closing the probe was part of the agreement Iran reached with the United States, Britain, China, France, Russia and Germany to limit its nuclear program in exchange for sanctions relief.
Amano concluded Iran carried out activities related to developing a "nuclear explosive device," mostly before 2003. But those activities did not get beyond scientific studies and acquiring "certain relevant technical competencies and capabilities."
The IAEA statement comes a day after Israeli Prime Minister Benjamin Netanyahu presented materials he said showed evidence Iran covered up nuclear arms work.
The White House praised the information as "new and compelling," though officials in Washington have stopped short of charging Tehran with outright violations of its 2015 deal with world powers.
U.S. officials reviewing the cache of documents, charts, blueprints, photos and videos recovered by Israeli intelligence said late Monday that the materials they had seen were authentic and consistent with information amassed by the U.S. over many years.
"This information provides new and compelling details about Iran's efforts to develop missile-deliverable nuclear weapons," White House Press Secretary Sarah Sanders said in a statement.
Netanyahu first leveled the new accusations Monday during a televised news conference, saying the cache of documents and other files show Iran was "brazenly lying" about its nuclear weapons program.
The initial response to Netanyahu's allegations was lukewarm. Intelligence experts and diplomats said much of the evidence the Israeli leader presented during his news conference dated to before Iran signed the 2015 nuclear deal.
Iran, too, downplayed the intelligence, with Iranian Foreign Minister Javad Zarif taking to Twitter to deride the Israeli claims.
"The boy who can't stop crying wolf is at it again," Zarif tweeted before Netanyahu spoke. "You can only fool some of the people so many times."
France's Foreign Ministry said Tuesday the information presented by Israel reinforces the need to keep the nuclear deal in place.
But U.S. officials say while much of the intelligence is consistent with what has long been known, some of it sheds new light on Tehran's activities.
Specifically, officials said the Israeli intelligence provided new details on Iran's effort to develop its Shahab-3 ballistic missile into one capable of delivering a nuclear warhead.
"I think this makes very clear that at the very least the Iranians have continued to lie to their own people," U.S. Secretary of State Mike Pompeo told reporters late Monday. "The Iranians have consistently taken the position that they've never had a program like this."
"It is time to revisit the question of whether Iran can be trusted to enrich or control any nuclear material," Pompeo said.
The new round of allegations against Iran comes at a critical time. The Trump administration has given U.S. allies a May 12 deadline to fix what it sees as the flaws with the 2015 nuclear deal, also known as the Joint Comprehensive Plan of Action. If that does not happen, Trump has threatened to pull the U.S. out of the deal and reimpose economic sanctions on Tehran.
U.S. President Donald Trump was likewise vague when he spoke earlier Monday during a White House news conference with Nigerian President Muhammadu Buhari.
"If anything is proven right what Israel has done today with the news conference… that is just not an acceptable situation," Trump said.
But he quickly added, "if anything, what's happening today and what's happened over the last little while, and what we've learned, has really shown that I've been 100 percent right."
"They're not sitting back idly. They're setting off missiles which they say are for television purposes," Trump said. "I don't think so."
As recently as last month, top U.S. military commanders, including the commander of U.S. Strategic Command, told U.S. lawmakers that Tehran is in compliance with the 2015 nuclear deal.
At the Pentagon Monday, U.S. Defense Secretary Jim Mattis refused to go into details when asked whether the U.S. believes Iran was in violation. But Mattis also reaffirmed comments he made to lawmakers last week that the deal was robust enough to deal with any potential violations.
National Security correspondent Jeff Seldin, White House correspondent Steve Herman and State Department correspondent Nike Ching contributed to this report.