The Islamic Republic’s nuclear spokesman, Behrouz Kamalvandi, flatly rejected Amano’s comments, effectively reiterating Supreme Leader Ayatollah Ali Khamenei’s insistence that regardless of any international suspicions or the demands of the six world powers with which Iran is negotiating, its relationship with the IAEA will be no more elaborate than that of every other signatory to the Nuclear Nonproliferation Treaty.

All of this strongly suggests that Tehran has something to hide.

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Iran’s secret nuclear program and its drive to obtain nuclear weapons are serious national security concerns for the West and the international community as a whole. At the core of negotiations between Tehran and the P5+1 world powers are two goals: establishing guarantees that Iran’s ruling theocracy, the world’s leading state sponsor of terrorism, will not obtain nuclear weapons and blocking all of its possible pathways to a bomb.

Existing concerns are aggravated by the Iranian regime’s two-decade-long track record of concealing its nuclear program, particularly the aspects pertinent to possible military dimensions. Any leniency in response to this obstinacy could result in catastrophic strategic consequences. In a word, the West can neither take any risks in this regard nor solely trust in Tehran’s promises, nor postpone the final determination of these issues for resolution after a possible final agreement.

What made the issue more urgent and more pressing was the revelation of detailed, specific information about the existence of a secret parallel system—in particular the existence of a secret site, “Lavizan-3,” in Tehran by the National Council of Resistance of Iran (NCRI) on February 25. According to the information provided by the Iranian opposition, Tehran has been enriching uranium secretly at this site for years, using advanced centrifuges.

In general, it is the mandate of the IAEA, as the eyes and ears of the international community on matters of atomic energy, to follow up on any credible lead. What makes this revelation more serious and more troubling is the record and credibility of the source.

The NCRI has exposed some of the most important dimensions of the Iranian regime’s nuclear weapons program, namely the Natanz uranium enrichment and the Arak heavy water facilities, the Kalay-e Electric centrifuge assembly and testing facility, the Lashkar-Abad laser enrichment facility, the Lavizan-Shian site, the Fordo underground enrichment site and the Defensive Innovation and Research Organization, which is wholly responsible for coordinating the Iranian military nuclear program.

In light of the steady accumulation of evidence that Iran has been concealing its actual nuclear ambitions from the world community, the IAEA is absolutely right to demand a much more aggressive inspections regime and far greater cooperation from Tehran before it is cleared of even the slightest suspicion.

At the same time, the P5+1 group of nations is wrong to not fully support that push for compliance, although it is worth noting that not every member of the group is equally culpable for this laxity. In its apparent desperation for a deal, the U.S. has dismissed several relevant concerns about Iran’s behavior; for instance, describing the testing of advanced centrifuges as a “mistake” and not a violation of the Joint Plan of Action. But France has maintained a harder line, challenging the U.S. over certain perceived Western concessions, such as limiting the duration of the final nuclear agreement to as little as 10 years.

The French approach to this issue has always been the more appropriate one, and this is even clearer in light of ongoing IAEA criticism and the latest revelation of a secret Iranian nuclear site. Hopefully, France, the U.S. Congress and other relevant players will provide sufficient support to the IAEA and will encourage it to demand immediate inspection of the Lavizan-3 site and make its findings public quickly.

Experience has shown that any procrastination would only allow Iran to alter the venue and destroy evidence and linkages to the military aspects of its nuclear program. This, of course, would make the IAEA’s work that much more difficult, and would by extension complicate nuclear talks that have always been expected to hinge on the outcome of the IAEA probe.

France and each of the Western negotiators must remain committed to that point as well. Any signing of an agreement with Tehran should be hinged upon the outcome of inspection of the Lavizan-3 site, the Parchin site and other pending and unanswered issues regarding the nature of the Iranian nuclear program.

Unless Tehran is compelled to comply with these demands, any belief regarding the peaceful and civilian nature of the Iranian nuclear program will be delusional, and there will be no credible assurance that Tehran’s pathways to obtaining nuclear weapons have been blocked.

Lord Alex Carlile of Berriew is a Liberal Democrat member of the U.K. House of Lords and co-chair of the British Parliamentary Committee for Iran Freedom (www.iran-freedom.org). Giulio Maria Terzi is a former Italian foreign minister.