The questions about Parchin come as Iranian Foreign Minister Ali Akbar Salehi said this week that Tehran is ready to resolve all questions about its nuclear program "very quickly and simply."
That promise comes amid a backdrop of threats of military action by Israel or the US, or both, to strike Iran's nuclear facilities; but also amid positive initial signals toward a diplomatic solution.
Iran and world powers – including the US, Russia, and China – last week resumed nuclear talks for the first time in 15 months. Both sides say concrete progress is possible at the next round on May 23 in Baghdad, if Iran agrees to limit its uranium enrichment and open completely to inspections, and if the world powers begin lifting crippling sanctions.
IAEA inspectors in January and November 2005 were given access to Parchin, a sprawling military base so large that it includes hundreds of buildings and underground structures.