Before the 2015 multilateral nuclear deal mainly negotiated by U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif, that would have taken only two months, but under the accord Iran was required to ship about 97 percent of its nuclear fuel out of the country and dismantle most its centrifuges.

Experts say the revelation that Iran had more advanced capabilities to make nuclear weapons themselves—as opposed to its ability to produce weapons-grade fuel, the main focus of the nuclear pact—is a surprising and troubling finding in the new intelligence.

“The archive is littered with new stuff about the Iranian nuclear weapons program,” Albright told Foreign Policy. “It’s unbelievable how much is in there.” One of his key conclusions from studying the documents was that the Iranians “were further along than Western intelligence agencies realized.”

The archive, which is well over 100,000 pages long, covers the period from 1999 to 2003, a decade before negotiations on a nuclear deal began. But the trove of documents demonstrates that Washington and the IAEA were constantly underestimating how close Tehran was to a bomb.