VIENNA -- The U.N. nuclear agency says Iran has neutralized about four-fifths of its stockpile of higher-enriched uranium that could be turned quickly into the core of a nuclear weapon.
The agency says Iran now has less than 90 pounds of the material. That's about a fifth of what it would need to for a weapon.
The U.N's International Atomic Energy Agency reported the development Friday in a confidential report obtained by The Associated Press.
Iran denies any interest in having atomic arms. But it has agreed to some nuclear concessions in exchange for a partial lifting of the sanctions that are crippling its economy under a deal in effect since January.
Diluting and converting its 20-percent enriched stockpile were among the Iranian commitments under the agreement.
Last week, an ambitious round of nuclear talks between Iran and six world powers ended with serious setbacks, with a senior Iranian official saying the two sides are at odds on several key issues.
Iranian Deputy Foreign Minister Abbas Araghchi told Iranian media that differences were too big to start the drafting process. He gave no immediate details beyond saying that both sides were apart on several issues.
"There was no tangible progress in this round of the talks," Araghchi said. "We will have one or two more rounds of talks in June. Talks will continue."
For Iran, the major sticking point is sanctions relief, reports CBS News correspondent Elizabeth Palmer.
President Obama's administration can offer to unblock tens of billions in frozen Iranian assets. However, the Iranians want more than that money. They want business links to the West, and access to the global banking system and financial markets.
Finally, the two sides fundamentally disagree on the length of time any comprehensive agreement would remain in effect, Palmer reports. The P5+1 are talking about decades, while Iran wants all restrictions lifted after a few years.
Trita Parsi, president of the National Iranian American Council, told Palmer that a long-term deal is unlikely.
"Iran will likely reject a deal that lasts beyond 10 to 15 years, not just because of the mistrust that exists between the two sides, but also because of the legitimate uncertainty that exists about the intentions and orientations of future leaders in Washington and Tehran." Parsi said.