File Photo: In this Jan. 15, 2011 image, a part of Arak heavy water nuclear facilities is seen, near the central city of Arak, 150 miles (250 kilometers) southwest of the capital Tehran, Iran
Diplomats say that a July 20 target date for an Iran nuclear deal is in jeopardy because Tehran is not providing answers sought by U.N. experts investigating whether Tehran worked on atomic arms.
The U.N. atomic agency suspects Iran may have tested detonators as part of secret work on nuclear weapons. But three diplomats told The Associated Press Monday that Iran insists they were used only for conventional military or civilian blasts.
The U.N. agency's probe is separate from nuclear talks between Iran and six powers, which both sides hope to finish by July 20. But the U.S. insists that Tehran dispel agency suspicions as part of any overall deal.
Iran denies any nuclear weapons aspirations. The diplomats demanded anonymity because they were not authorized to reveal the information.