VIENNA (Reuters) - The U.N. atomic agency has corrected data to lower its estimate of the size of Iran's uranium stockpile, a figure watched ahead of this month's deadline for Tehran and six world powers to settle a dispute over Iran's nuclear programme.
The International Atomic Energy Agency (IAEA) now estimates that Iran's holding of low-enriched uranium gas is 8,290 kg, 100 kg less than it had said in a confidential report last week, diplomats said on Thursday.
There was no explanation of why the initial figure was wrong, or the significance of the discrepancy, and there was no immediate IAEA comment.
Iran's stock of uranium refined to a fissile concentration of up to 5 percent is a sensitive issue because, if processed much further, the material could provide the explosive core of a nuclear weapon.
Iran says it does not aim to develop atomic bombs.
The issue is in focus ahead of a Nov. 24 target date for Iran and the global powers to reach a broad diplomatic deal to settle their standoff, as one idea under discussion is for Tehran to ship part of its enriched uranium to Russia.
In Friday's report on Iran's nuclear programme, the IAEA said the stockpile had grown by 625 kg to nearly 8.4 tonnes since its previous report in early September.
But in a correction issued to IAEA member states this week both figures were reduced, to 525 kg and 8,290 kg respectively, according to the data seen by Reuters.
Iran's uranium stockpile is one of the factors that could determine how much time it would need for any attempt to assemble nuclear weapons. Iran says it only refines uranium to fuel nuclear power plants but the West wants to make sure the country cannot produce an atomic bomb any time soon.
Iran and the six states - the United States, France, Germany, Russia, Britain and China - will meet in Vienna from Nov. 18 to try to seal a long-term agreement that would dispel fears the standoff could plunge the Middle East into a new war.
The IAEA also corrected another figure in its Nov. 7 report, reducing the number of advanced IR-6 uranium enrichment centrifuges installed at its Natanz research and development site to nine from 19.
(Reporting by Fredrik Dahl; editing by Ralph Boulton)