Iran began establishing an underground nuclear test site in the early 2000s and developed the necessary steps towards making an explosive device as part of a program called “Project Midan,” according to a new report.

The initiative, which had a start date of Dec. 12, 2000, had spotted five possible testing sites and was developing processes, including seismic ones, to measure an underground nuclear test’s explosive yield, according to the report from the Institute for Science and International Security.

Citing “geospatial information,” the institute detected a site “where underground non-nuclear explosives tests were conducted in 2003 as part of developing seismic methods of measuring the yield of an underground nuclear explosive.”

The report called on the International Atomic Energy Agency to respond to the archives as they apparently contradict Iran’s statements about its nuclear program, which violates the Nonproliferation Treaty (NPT), which Iran has been party to since 1970.

Last year, Israeli Prime Minister Benjamin Netanyahu presented evidence collected by Israeli intelligence that, based on some 55,000 pages of documents and 55,000 files on CDs, showed that “Iran is brazenly lying when it says it never had a nuclear-weapons program. The files prove that.”

It was proof of the existence of “Project Amad,” an initiative the regime had built to design, construct and test nuclear weapons that ended in 2003, although Netanyahu warned that Iran has continued this program covertly.