Israel’s Prime Minister Benjamin Netanyahu on Monday said Israel is in possession of tens of thousands of documents and discs that prove that Iran lied about the history of its nuclear weapons program when it signed the 2015 nuclear deal. 

In a televised speech from Tel Aviv, Netanyahu dramatically pulled a curtain away from a shelf of files that he said were copies of some of the 55,000 documents that Israel had obtained from Iran’s secret nuclear archive. Most of the documents, as described, dated from 2003 and before, when Iran had a clandestine weapons development program dubbed “Project Amad.”

The speech came at a critical time for the nuclear deal, just ahead of a May 12 deadline for President Trump to decide whether to continue to waive statutory sanctions that were lifted as part of the agreement.

In his remarks, Netanyahu said the cache confirmed something that has not been in dispute among signatories of the deal — that Iran has lied about its past nuclear efforts. He has waged a fierce campaign for the pact to be changed or scrapped, often repeating the mantra “fix it or nix it” — concerned that it will enable Israel’s archrival to come closer to developing a nuclear weapon. 

Trump, speaking at a Washington news conference with the president of Nigeria, said Netanyahu’s revelations “showed that I’ve been 100 percent right” in describing the nuclear agreement as the “worst deal” ever signed. “We’ll see what happens,” he said of the coming deadline.

Richard Nephew, a former senior State Department official who was part of the U.S. team that negotiated the deal implemented in January 2016, said Netanyahu’s revelations were “interesting, and important for building a history of [Iran’s] program. But it is not a new revelation, at least in terms of where the program was when we were negotiating.”

“To put it another way,” he said, “it is why we negotiated the JCPOA,” or Joint Comprehensive Plan of Action.

“What he is revealing with all this detail is not news,” said Daryl Kimball, executive director of the Arms Control Association. “The fact that Iran has experimented with nuclear warhead designs, and had at one point an active weapons program, makes it all the more essential that the JCPOA remains in place to prevent Iran from quickly amassing enough fissile material for even one bomb.”

“It is ludicrous to recommend . . . that the deal should be dismantled, which would open a pathway for Iran to pursue” a nuclear weapon, Kimball said.

Iranian officials have said that if the deal is canceled, they would quickly increase both the quantity and quality of centrifuges, now restricted under the deal, which would allow them theoretically to produce weapons-grade uranium.

Secretary of State Mike Pompeo said that the administration had known about the documents for “a while,” and said “I can confirm…these documents are real…they’re authentic.”

Speaking to reporters aboard his aircraft returning from an overseas trip that included a Sunday stop in Israel, Pompeo agreed that existence of the Iranian program Netanyahu described “has been known for quite some time.” But, he said, the documents provided “new information” about the “scope and the scale of the program.” He said the administration had been given a copy of the material but had not yet gone through all of it yet.

He said that the Iranians kept the documents “for a purpose,” but did not speculate on what it was. In his confirmation testimony in mid-April, Pompeo agreed that the International Atomic Energy Agency had so far concluded Iran was in compliance with the terms of the deal, and that he did not believe Tehran had been, or would be, in a “rush” to build a nuclear weapon, regardless of what Trump decided to do.

The White House, which initially issued a statement saying that the information showed Iran “has a robust, clandestine nuclear weapons program,” quickly issued a clarification indicating the use of the present tense was a “clerical error.” A spokesman for the National Security Council said that the Israeli presentation described “an Iranian effort from 1999-2003 to develop nuclear weapons.”

 Netanyahu’s statement “adds new and compelling details” on the past Iranian program, according to the spokesperson, who spoke on the condition of anonymity under White House ground rules.

In a dramatic presentation, Netanyahu stood on a stage with a pointer. To one side was a bookcase filled with shelves of files that he said were Iran’s secret nuclear records, apparently obtained through a covert operation by Israeli intelligence. Next to it was a display cabinet of compact discs.

Standing in front of a screen, Netanyahu displayed slides from the files that revealed the breadth of the Iranian nuclear program. Showing excerpts from what he said was “half a ton” of documents on a screen behind him, Netanyahu said they demonstrated conclusively that Iran had not “come clean” on its program. Iran has repeatedly insisted that it never has had and never would have a weapons program. 

The documents indicated that Iran had been proceeding with “five key elements of a nuclear weapons program,” he said, including designing a weapon, developing nuclear cores and building implosion systems, preparing test sites and integrating nuclear warheads on ballistic missiles.

“These files conclusively prove that Iran is brazenly lying when it says it never had a nuclear weapons program,” Netanyahu said. “This is just a fraction of the total material we have,” he said.

Iranian Foreign Minister Mohammad Javad Zarif mocked Netanyahu as the “boy who can’t stop crying wolf,” tweeting a picture of the Israeli prime minister holding up a diagram of a cartoonlike bomb that he used to illustrate the Iranian nuclear threat during a speech to the U.N. General Assembly in 2012. 

“Trump is jumping on a rehash of old allegations already dealt with by the IAEA to ‘nix’ the deal,” Zarif added, referring to the International Atomic Energy Agency. “How convenient.”

The timing of Netanyahu’s presentation seemed designed for maximum impact on Trump’s decision.

“I am sure this was all fully coordinated with the Trump administration,” said former U.S. ambassador to Israel Dan Shapiro, a fellow at the Institute for National Security Studies. He said the information was “not new” but described the retrieval of so many files from Iran as an “intelligence coup.”

Trump has specifically cited the sunset clauses in the agreement, its monitoring and verification provisions, and its failure to address Iran’s ballistic missile program as flaws that must be “fixed.”

European allies that signed the deal — along with Russia and China — have been negotiating with the State Department on supplemental agreements to address Trump’s concerns without changing the nuclear agreement itself. In visits to Washington last week, French President Emmanuel Macron and German Chancellor Angela Merkel appealed to Trump to keep the deal in place.

Pompeo said that conversations with the Europeans were ongoing, and “we know what it is they’re hoping to achieve.” Even if Trump decides to pull out of the deal, he said, “I’m confident that we will continue to have good relations with our European partners.”

“I’ve been a longtime advocate of fixing” flaws in the deal rather than tearing it up, said Mark Dubowitz, CEO of the Foundation for Defense of Democracies. “Today’s revelations just make that much more difficult,” he said. “Not because [Netanyahu] revealed anything we didn’t know about Iran’s nuclear program. What he revealed is that Iran took all the instructions for making a nuclear bomb and buried them deep away from the prying eyes of the IAEA and Western intelligence”

As the May 12 U.S. deadline approaches, Netanyahu said he is sure Trump will “do the right thing for the United States, the right thing for Israel and the right thing for the peace of the world.” His announcement was made largely in English, a sign that he wanted his message spread to an international audience. 

Tensions between Iran and Israel have significantly ratcheted up in recent weeks. The announcement came just a day after a set of airstrikes in Syria that a monitoring group and some pro-Syrian media blamed on Israel. 

Israeli officials have declined to comment but admitted to hitting more than 100 targets inside Syria over the course of the civil war there. Israel has said it will not allow Iran or its proxies to build a military presence in Syria. 

Shortly after Netanyahu spoke on Monday, Israel’s parliament voted to expand his powers to declare war, allowing him to do so with only the approval of the defense minister in “extreme situations.”

DeYoung reported from Washington. Ruth Eglash in Jerusalem contributed to this report.