The United States says Iran has showed "zero progress" in satisfying demands by the international community for transparency in its nuclear program.
The comment by Gregory Schulte, the U.S. ambassador to the International Atomic Energy Agency, comes after a new report by the UN's nuclear watchdog that says its investigation into intelligence allegations of secret atom bomb research in Iran has reached a standstill because of Tehran's noncooperation.
"At every junction, on every request, they are saying 'no' to the IAEA inspectors," Schulte told RFE/RL's Radio Farda in an exclusive interview. "The IAEA wants Iran to implement the additional protocol; Iran refuses. The IAEA has asked for access to the workshops where centrifuges are being built; Iran refuses. The IAEA has asked for early information on new nuclear sites; Iran refuses."
The IAEA also said Iran continues to defy UN demands by refusing to suspend uranium enrichment. It says Iran currently has 3,820 centrifuges enriching uranium, with over 2,000 more being installed.
Iran maintains that its nuclear program is for purely peaceful purposes.
'Serious Concern'Schulte said Iran's "stonewalling" on the issue of its possible work on the design of a nuclear device, or "weaponization," is a "matter of serious concern."
"The report I have in front of me talks about how this information about weaponization has been derived from multiple sources over different periods of time, detailed in content, and generally consistent," Schulte said. "This is not material from the United States. This is material the IAEA says they have gotten from about 10 different countries. And it is not just studies. It is indication that Iran has engaged in studies, engineering work, testing, procurement, all related to the design of a nuclear weapon and the integration into a delivery system like the Shahab III missile."
Schulte said the United States will continue to move forward with additional sanctions on Iran, while saying Washington is also committed to the six-party talks on Iran's nuclear program, which involve the United States, China, Russia, Britain, France, and Germany.
"I know that there are authorities in Iran who are suggesting that the six are no longer together, but they are together," Schulte says. "And the six are very much committed...to a dual-track strategy of offering a negotiated way out to the Iranian authorities, one that has very generous terms, one in which the United States will sit down with Iran and others as an equal at the table."