Washington: Senior Obama administration officials said on Thursday they were struck by the number of significant technical problems Iran appears to be encountering on the road to a nuclear weapon.
The US officials, briefing reporters on a new International Atomic Energy Agency report, said Tehran is showing more evidence of trying to move toward a nuclear weapons capability but may be running out of uranium.
"The fact that they have increased the level of non-cooperation indicates to me that unless we can mount the international pressure to stop it, this program is heading more and more in the direction of seeking a weapons capability," one official said.
It may take Iran longer to build a weapon because of the technical problems, the official said, "but the pattern of behaviour is one that I think is very disturbing."
The IAEA report comes as the United States seeks an international consensus around tougher economic sanctions against Tehran, which denies seeking to develop a nuclear weapon and says it wants to produce peaceful atomic energy.
The officials said the evidence in the report indicates the Iranians are running into trouble with centrifuge machines used for enriching uranium.
"They only have 23 of 52 cascades running and running in the sense of producing low-enriched uranium," one official said. "It seems to be consistent with technical problems they`re having in terms of operating centrifuges."
The official said Iran seems to have a total stockpile of about 2,000 kg (4,400 pounds) of low-enriched uranium.
"So they are still accumulating low-enriched uranium but at a fairly low rate compared to what they should be able to do on paper," the official said.
Uranium for a nuclear power reactor needs to be at an enrichment level of 5 percent. Iran has been seeking to enrich uranium to a 20-percent level.
The official said Iran seems to be "at least several years" away from accumulating sufficient quantities of 20 percent enriched uranium that would be necessary for converting into bomb-grade material. Uranium enrichment of 90 percent or more is needed for a weapon.
The report also provides support for a theory that Iran could be running out of natural uranium by an apparent inability to produce feed material for their centrifuges.
The officials said the IAEA report raised questions about Iran`s claim it began building the formerly secret Qom facility in the second half of 2007 and that it appeared to have been begun in 2006.
The Obama administration leaped on the disclosure of the facility`s existence last autumn as proof of Iran`s weapons intentions. The officials said it now appeared there was little activity at the facility.