However, most of the tip-offs about supposed secret weapons sites provided by the CIA and other US intelligence agencies have led to dead ends when investigated by IAEA inspectors, according to informed sources in Vienna.
"Most of it has turned out to be incorrect," a diplomat at the IAEA with detailed knowledge of the agency's investigations said.
"They gave us a paper with a list of sites. [The inspectors] did some follow-up, they went to some military sites, but there was no sign of [banned nuclear] activities.
"Now [the inspectors] don't go in blindly. Only if it passes a credibility test."
One particularly contentious issue was records of plans to build a nuclear warhead, which the CIA said it found on a stolen laptop computer supplied by an informant inside Iran.