VIENNA -- The U.N. atomic energy agency is preparing to wrap up a more than decade-long investigation of suspected nuclear weapons work by Iran, the agency's chief said Thursday.
But its report will stop short of delivering a judgment on whether the suspicions are valid.
The report by the U.N.'s International Atomic Energy Agency is meant to put the issue to rest after years of attempts to investigate the allegations. The U.S. and its allies say Tehran conducted past research and development of such weapons. Iran says the accusations are based on false intelligence from its adversaries.
The issue has dominated International Atomic Energy Agency meetings, contributed to U.N. Security Council resolutions against Iran and is now playing a role in determining whether sanctions against Tehran will be lifted under a nuclear deal that is expected to be implemented early next year.
But the comments by agency chief Yukiya Amano made clear that his assessment will contain enough gray zones to leave the question unresolved.
The report "won't be black and white," Amano told reporters outside a meeting of the agency's 35-nation board. He described his report as a "jigsaw puzzle" for which his agency has "pieces."
While he said it was up to board members to decide whether to close the investigation on the basis of his report, diplomats briefed on the investigation said Thursday that outcome was likely.
"This is an issue that can't be answered by 'yes' or 'no,"' Amano said.
He said he and his colleagues "highly appreciate the dialogue between Iran and the IAEA."
Formally, the report will help determine whether Iran gets relief from sanctions in exchange for paring back its atomic activities under a July 14 deal Tehran signed with six world powers.
Oil and banking sanctions against Iran could be lifted by mid-January based on the pace at which technicians are removing and mothballing nuclear equipment at the country's uranium- enrichment facilities.
Iran removed 4,530 centrifuges during the 28 days ending Nov. 15, a rate of 162 machines per day, according to the agency. Iran may be able to fulfill its part of the nuclear accord by Jan. 12, based on current removal rates.
Two diplomats said the U.S. and the five other powers that negotiated the nuclear deal with Iran were unlikely to be too critical of the report, not wanting to jeopardize agreement. But expectations remain that Iran has continued either to deny the activities under investigation or insist they were part of peaceful nuclear research. They demanded anonymity because they weren't authorized to discuss the issue.
Iranian Deputy Foreign Minister Abbas Araghchi warned Wednesday that Amano and the board must "meet the stipulated commitments" -- shorthand for closing the books on the allegations. Otherwise, he warned, Tehran will not hew to its obligations under the larger nuclear deal.
Amano said his report will be circulated among board members next week, with a special Dec. 15 meeting to be convened for a decision on whether to declare the investigation closed.
Information for this article was contributed by George Jahn, Jelena Vicic and Nasser Karimi of The Associated Press and by Jonathan Tirone of Bloomberg News.
A Section on 11/27/2015