The archive of Iranian nuclear documents seized by the Israeli Mossad from a Tehran warehouse in January shows that Iran’s program to build nuclear weapons “was almost certainly larger, more sophisticated and better organized” than was suspected, unnamed nuclear experts were quoted as saying in the New York Times on Sunday, after being shown selected documents from the haul by US reporters.

One of the Iranian documents specifies plans to build a first “batch of five weapons” and discusses sites for possible underground nuclear tests, the Times reported, after one of its reporters was given limited access to the haul last week, along with a reporter from the Washington Post, and another from the Wall Street Journal.

“None were built, possibly because the Iranians feared being caught, or because a campaign by American and Israeli intelligence agencies to sabotage the effort, with cyberattacks and disclosures of key facilities, took its toll,” said the Times.

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“It’s quite good,” Robert Kelley, a nuclear engineer and former inspector for the UN’s nuclear watchdog, the IAEA, told The Times dryly, after being shown some of the documents. “The papers show these guys were working on nuclear bombs.”

The documents also reinforce Israel’s contention that Iran remains determined to attain a nuclear weapons archive, despite its commitments under the 2015 nuclear deal (the JCPOA), the US reporters noted.

The materials they were shown include documentation that names current Iranian President Hassan Rouhani as a member of the “Council for Advanced Technologies” that approved the rogue nuclear weapons program, the Washington Post said, and indicate “a supporting role by Iran’s Islamic Revolutionary Guard Corps, as well as the Quds Force.” Previously released documents indicate that the Iranian army was charged with overseeing the conversion of low-enriched uranium to weapons-grade fuel suitable for nuclear bombs.

The three US reporters were given limited access to the trove last week, and were briefed by Israeli officials. Israel, which unveiled the documents in April, has been mining the trove of 100,000 documents for new information, and has also shared the material with the IAEA and with US and European intelligence agencies. US President Donald Trump withdrew from the JCPOA in May, soon after Netanyahu publicly presented the haul at a press conference, in which he declared that “Iran lied” when claiming not to seek nuclear weapons.

The thrust of last week’s briefing for the US press was to highlight how far the nuclear program had progressed — Iran “was on the cusp of mastering key bombmaking technologies when the research was ordered halted” in 2003, the Washington Post said — and to underline Israel’s insistence that the archive demonstrates that the Iranian regime has not abandoned its effort to obtain a nuclear weapons arsenal, but has merely mothballed parts of it.

“These documents are old, but they have a bearing on the future,” a senior Israeli official was quoted by the Post as saying. “It’s not a history lesson. They have capabilities they can use in the future.”

Iran halted much of the nuclear weapons program in 2003, but internal memos in the archive “show senior scientists making extensive plans to continue several projects in secret, hidden within existing military research programs,” said the Washington Post.

“Let there be no mistake: the amount of personnel in the overt and covert parts will not decrease,” it quoted an Iranian official writing in a memo dated September 3, 2003. “The structure will not become smaller, and every sub-project will supervise both its overt and covert parts.”

“In a few years, when some of the JCPOA’s restrictions expire, Iran will be in a position to resume work on a nuclear device that Israel sees as a threat to its existence,” the Israeli official told the Post.

The seized archive “explains why the [nuclear deal] to us is worse than nothing, because it leaves key parts of the nuclear program unaddressed,” the Israeli official said, echoing Netanyahu’s frequent contention. “It doesn’t block Iran’s path to the bomb. It paves Iran’s path to the bomb.”

The Washington Post said US intelligence agencies have long believed that “Iran has kept the intellectual core of its nuclear program intact.” And the documents showcased by Israel detail several meetings in late 2003 in which the Iranian nuclear project chiefs “discuss ways to keep the program’s scientists busy with nuclear-relevant research,” even after it was ostensibly frozen.

The Tehran warehouse from which the documents were purloined “was put into use only after the 2015 accord was reached with the United States, European powers, Russia, and China,” the Times reported. Israeli officials contend that the fact that the Iranians “systematically went about collecting thousands of pages spread around the country documenting how to build a weapon, how to fit it on a missile and how to detonate it” demonstrates that they fully intend to return to the effort of nuclear weapons building when the opportunity arises.

The three US reporters were permitted to see and touch, with gloves on, “a few pages of original files, including handwritten notes signed by Mohsen Fakhrizadeh, the Iranian physicist who Western intelligence agencies say was in charge of [the Iranian program] Project Amad,” the Washington Post said. “Journalists were given copies of some documents, including several that were previously unpublished. Others were shown only briefly or not at all, on the grounds that they contained explicit technical details that could be used to make nuclear weapons.”

The documents show that Iran obtained “explicit weapons-design information from a foreign source,” the Washington Post said. “We see explicit material related to nuclear weapons from different sources, some of it not Iranian in origin,” an Israeli intelligence official said. Israeli officials would not say whether the bomb design information was provided by a state or by an individual. Iran is known to have obtained assistance in building uranium-enrichment centrifuges from Pakistani scientist Abdul Qadeer Khan, who is also believed by US intelligence to have given “partial blueprints for a Chinese nuclear device to at least one of his international customers,” the Washington Post said.

“Iran had foreign help, though Israeli officials held back any documents indicating where it came from,” said the New York Times. “Much was clearly from Pakistan, but officials said other foreign experts were also involved — though they may not have been working for their governments.”

The archive confirms that the covert Iranian nuclear program was launched in the late 1980s and halted in 2003, when Iran feared a US invasion, and when its secret uranium enrichment plant at Natanz was exposed. While this was known, revelations in the archive include “previously unknown photos of a large cylindrical test chamber in which Iran is said to have conducted tests of an implosion device of the type used to trigger a nuclear detonation,” the Washington Post said.

The US reporters were also shown documents that show Iran was “measuring radiation from a neutron-generating explosive test inside the same chamber in 2002,” it added. “In modern nuclear weapons design, a neutron generator releases radioactive particles to help sustain a powerful nuclear chain reaction.”

The reporters were also shown documents and photographs detailing Iranian work on “making a form of uranium metal that can be used as a neutron initiator, and still others [that] describe problems with uranium contamination outside the test chamber, which was located at the Parchin military base outside Tehran.”

The Post noted that when the UN sought to inspect the Parchin test site years later, Iran first “completely dismantled the test chamber, scraped away several tons of topsoil, cut down nearby trees and covered the entire area with fresh asphalt.”

Reported the Times: “By the time the head of the International Atomic Energy Agency, Yukiya Amano, was finally permitted to visit the site in 2015, it was empty, though the agency’s report indicated that it looked as if equipment had been removed. The photos [shown to the reporters by Israel] indicate that is exactly what happened: They show a large chamber that nuclear experts say is tailor-made for the kind of experimental activity that the international inspectors were looking for….

“The chamber appears to be part of neutron experiments that strongly point to an effort to build nuclear weapons,” added the Times. “Nuclear explosions start when fast-moving particles known as neutrons split atoms of nuclear fuel in two, producing chain reactions that release more neutrons and enormous bursts of energy. At the core of an atom bomb, a device known as a neutron initiator — or sometimes a spark plug — creates the initial wave of speeding neutrons.”

In the documents, one of the Iranian scientists, Masoud Alimohammadi, warns that work on neutron-generated chain reactions for a nuclear explosion must be kept secret at all costs. “‘Neutrons’ research could not be considered ‘overt’ and needs to be concealed,” Alimohammadi’s notes say. “We cannot excuse such activities as defensive. Neutron activities are sensitive, and we have no explanation for them.” Alimohammadi, the Times noted, was assassinated in January 2010.

While Israel argues that the archive underlines how Iran fooled the West, and that the 2015 agreement is a terrible mistake, an assessment shared by the Trump administration, the Washington Post noted that “proponents say the pact has permanent provisions that will alert inspectors and spy agencies quickly if Iran begins work on an actual weapon.”

Under Tehran’s nose

Israeli officials also gave the three US reporters additional, but not full, details of the operation to seize and bring home the Iranian archive, some of which has been previously detailed.

Israel established early last year that the materials related to the Iranian program were being collected at a single warehouse in the Shorabad district of southern Tehran. The anonymous building had no overt security, and very few Iranians knew of its existence, the Israeli officials said last week.

“Mossad agents were able learn the internal layout of the building, including the location and general contents of 32 safes that contained paper records, photos and computer-storage files from ‘Project Amad,’” the Washington Post said.

“Clearly, the Israeli spies had inside help,” the Times claimed, without elaboration.

They decided to carry out the operation on January 31, and assessed that they had “a time window of exactly six hours, 29 minutes, in which they believed they could breach the facility, open the safes and remove half a ton of documents without being detected,” said the Post.

In that time, they had to “disable the alarms, break through two doors, cut through dozens of giant safes and get out of the city with a half-ton of secret materials,” said The New York Times. “The agents arrived that night, Jan. 31, with torches that burned at least 3,600 degrees, hot enough, as they knew from intelligence collected during the planning of the operation, to cut through the 32 Iranian-made safes.”

The Mossad team knew guards would arrive at 7 a.m., and were ordered to finish by 5 a.m., so that they would also have time to escape. “When time was up, they fled for the border, hauling 50,000 pages and 163 compact discs of memos, videos and plans,” said the Times. Fewer than 24 agents were directly involved in the break-in, it said, though Israeli officials have previously indicated more than 100 personnel were involved in the overall operation.

“In most Mossad operations, spies aim to penetrate a facility and photograph or copy material without traces,” the Times noted. “But in this case, the Mossad chief, Yossi Cohen, ordered that the material be stolen outright. That would drastically shorten the time the agents spent inside the building. But the Israelis wanted to be able to counter Iranian claims that the material was forged and offer it up for examination by international groups.”

Not all the material in the archives was removed. The Israeli officials did not detail how the material was brought out of Iran, or even whether it left Iran via land, air, or sea. They said only that it was removed via “several different routes” and that there was no chase. “At exactly 7 a.m., as the Mossad expected, a guard arrived and discovered that the doors and safes were broken. He sounded the alarm, and the Iranian authorities soon began a nationwide campaign to locate the burglars,” said the Times.

The Iranian bid to find the thieves involved “tens of thousands of Iranian security and police personnel,” an Israeli official said, but Iran maintained a public silence over the heist from under its nose. Until Netanyahu unveiled the haul in April, “the Iranians never said a word in public about what had happened.”

What Netanyahu said

Unveiling the archive in April, Netanyahu called the Mossad operation one of the “greatest achievements” of Israeli intelligence. “You may well know that Iran’s leaders repeatedly deny ever pursuing nuclear weapons,” he said. “Iran lied. Big time.”

The cache, he said, contained “incriminating documents, incriminating charts, incriminating presentations, incriminating blueprints, incriminating photos, incriminating videos and more.”

Netanyahu said Project Amad included five key elements — designing nuclear weapons, developing nuclear cores, building nuclear implosion systems, preparing nuclear tests, and integrating nuclear warheads on missiles. Amid growing pressure, Iran decided to shut down Project Amad in 2003, Netanyahu said, instead splitting its nuclear program into covert and overt tracks in order to avoid scrutiny.

“This is exactly what Iran continued to do,” said Netanyahu. “Iran planned at the highest levels to continue work related to nuclear weapons — under different guises and using the same personnel. What I’ve shown you tonight is just a fraction of the total material that we have. But even from this fraction you can draw four main conclusions. First, Iran lied about never having a nuclear weapons program,” said Netanyahu.

Second, “Even after the deal, Iran continued to preserve and expand its nuclear know how for future use.” Third, “Iran lied again in 2015, when it didn’t come clean to the IAEA as required by the unclear deal.” And fourth, he said, “The nuclear deal is based on lies. It is based on Iranian lies and Iranian deception… 100,000 files right here prove that they lied.”