"We categorically deny any nuclear-related testing at Parchin," Well, that may be true, but the original compaint was in regard to "high-explosives" testing - you know, like the kind North Korea use to blow the top off one of their mountains ostensibly as part f a dam construction project.
Here's a link that describes Parchin.
http://www.globalsecurity.org/wmd/world/iran/parchin.htm"On 11 September 2004 it was reported that the IAEA had requested a
visit to Parchin, but the Iranians had not yet agreed to the
inspection. The IAEA questioned whether Iran might be doing nuclear
weapons work there. The agency had requested to send inspectors to
Parchin, but this was not mentioned in the IAEA report on Iran
published 01 September 2004.
One area at Parchin may be assessed as a "probable" nuclear weapons
development facility. The extensive weapons development activity at the rest of the complex makes it an entirely logical location for weaponization work for Iran's atomic bomb program. The overall Parchin
complex represents is the leading center of Iran's munitions industry,
so a nuclear weapons program would already have all the expertise
needed within commuting distance. The suspect site is physically
isolated from the rest of the complex, suggesting that it is not part
of the conventional ammo, poison gas or missile programs. The recent
construction activity is also consistent with the recent construction
activity at other parts of Iran's bomb program, and the recent
completion is consistent with estimates of when Iran would get the
bomb."