Iran has given UN inspectors key documents about activities that could be used to make a nuclear weapon and allowed them to question a senior official suspected of involvement in the program, diplomats and officials said Thursday. The agency hoped Iran's recent decision to cooperate with the International Atomic Energy Agency (IAEA) will shed light on whether the country's military engaged in secret uranium enrichment activities, the diplomats and officials told The Associated Press on condition of anonymity because of the sensitivity of the investigation. At issue are the quantity and location of centrifuge and related technology the country acquired on the black market starting in the 1980s which can enrich uranium to low-grade fuel or the fissile core for nuclear warheads. There are suspicions that some of the material has not been declared to the IAEA and had been used by the military for a nuclear weapons program. A US official described Iran's decision to cooperate on the documents and permitting questioning of the official after nearly two years of foot-dragging as "important concessions."