U.S. Secretary of State John Kerry has said the United States has never had any doubts that Iran conducted work on nuclear weapons.
The real issue, Kerry said, was what Tehran will do now to adhere to the nuclear deal reached in July between Tehran and six world powers.
Speaking in Athens on December 4, Kerry declined to comment on this week's report by the UN nuclear agency that activities in Iran related to a nuclear explosive device occurred before 2003, with some activities continuing up to 2009.
Kerry said the international nuclear agreement with Iran made certain that "none of what happened in the past can happen in the future" and that is the "real issue."
Under the deal, sanctions against Tehran will be lifted in exchange for restrictions on its nuclear activities.
The report by the International Atomic Energy Agency will be taken up by the agency's 35-country board in mid-December.