Diplomats: UN report will show Iran cutting half of uranium stock closest to nuke-arms grade

European foreign policy chief Catherine Ashton and Iranian Foreign Minister Mohamad Javad Zarif, from left, arrive to address the media after closed-door nuclear talks in Vienna, Austria, Wednesday, April 9, 2014. (AP Photo/Ronald Zak) (The Associated Press)

European foreign policy chief Catherine Ashton and Iranian Foreign Minister Mohamad Javad Zarif, from left, arrive to address the media after closed-door nuclear talks in Vienna, Austria, Wednesday, April 9, 2014. (AP Photo/Ronald Zak) (The Associated Press)

Diplomats say the U.N. will certify later this week that Iran's ability to make a nuclear bomb has been reduced because it has neutralized half of its material that can be turned quickly into weapons-grade uranium.

The move is part of Iran's commitments under a deal that mandates nuclear concessions by Tehran in exchange for a partial lifting of sanctions crippling its economy.

Iran says it does not want nuclear weapons. But by January, it had amassed nearly enough 20 percent enriched uranium to be able to quickly make a nuclear bomb with further enrichment.

Two diplomats told The Associated Press Wednesday that a U.N. nuclear agency report will say that Iran has diluted half of that 20 percent stockpile to less proliferation-sensitive material.

They demanded anonymity because their information is confidential.