VIENNA — The U.N. atomic agency has received new and significant intelligence over the past month that Iran has moved further toward the ability to build a nuclear weapon, diplomats tell The Associated Press.
They say the intelligence shows that Iran has advanced its work on calculating the destructive power of an atomic warhead through a series of computer models that it ran sometime within the past three years.
The diplomats say the information comes from Israel, the United States and at least two other Western countries. The time-frame is significant because if the International Atomic Energy Agency decides that the intelligence is credible, it would strengthen its concerns that Iran has continued weapons work into the recent past — and may be continuing to do so.
Because computer modeling work is normally accompanied by physical tests of the components that go into a nuclear weapons, it would also buttress IAEA fears outlined in detail in November that Tehran is advancing its weapons research on multiple fronts.
"You want to have a theoretical understanding of the working of a nuclear weapon that is then related to the experiments you do on the various components," said David Albright, whose Washington-based Institute for Science and International Security is a frequent go-to source on Iran for Congress and other U.S. government branches. "The two go hand-in-hand."
Such computer mock-ups typically assess how high explosives compress fissile warhead material, setting off the chain reaction that results in a nuclear explosion. The yield is normally calculated in kilotons.
Any new evidence of Iranian research into nuclear weapons is likely to strengthen the hand of hawks in Israel who advocate a military strike on Iran. They argue that Tehran is deliberately stalemating international efforts at engagement while continuing its clandestine weapons work.
Iran denies any interest in nuclear weapons and says suspicions that it ever tried to develop them are based on fabricated U.S, Israeli and other intelligence. At the same time, it has blunted IAEA efforts to investigate such claims for more than five years.
It also has scoffed at Western allegations that it is enriching uranium to make the core of nuclear warheads, saying it seeks only to create reactor fuel. But it refuses to accept offers of such fuel from abroad and is now producing material that is easier to turn into weapons-grade uranium than its main, lower-enriched stockpile.
Although some of the new information was said to have been supplied by the United States, it appears to run counter to the stated U.S. position that Iran shut down wide-ranging secret research and development of the components of a nuclear weapons program in 2003. At the same time the U.S. fears that Iran continues to move toward the threshold of making such arms by enriching uranium.
Ali Asghar Soltanieh, Iran's chief IAEA delegate, cut short a telephone request for comment, saying he could not talk because he was in a meeting. In Tehran, meanwhile, Foreign Ministry spokesman Rahmin Mehmanparast told reporters that Iran will start answering the agency's "questions and concerns" only when "our rights and security issues" are recognized.
IAEA spokeswoman Gill Tudor said the agency would not comment. But four of six diplomats who spoke to the AP on the issue said an oblique passage in the IAEA's August Iran report saying "the agency has obtained more information which further corroborates" its suspicions alludes to the new intelligence.
All six demanded anonymity because they were not authorized to discuss classified information member countries make available to the IAEA.
Two of them said the new information builds on what the agency previously knew, not only because the research was apparently performed past 2009 but also because it reflects that Iran has allegedly moved closer to the overall ability to develop a nuclear weapon.
The IAEA first outlined suspicions in November that Iran was working on calculating the yield of a nuclear weapon, as part of a 13-page summary of Iran's suspected nuclear weapons work that it said was based on more than 1,000 pages of research and intelligence from more than 10 member nations.
It said then that "the modeling studies alleged to have been conducted in 2008 and 2009 by Iran ... (are) of particular concern," adding that the purpose of such studies for calculating anything other than nuclear explosion yields is "unclear to the agency."
Albright, of the Institute for Science and International Security, said such computer-run modeling is "critical to the development of a nuclear weapon."
George Jahn can be reached at http://twitter.com/georgejahn
Associated Press writer Nasser Karimi contributed from Tehran.