Several hundred tons of conventional explosives are missing from a former Iraqi military facility that once played a key role in Saddam Hussein's efforts to build a nuclear bomb, the U.N. nuclear agency confirmed Monday. International Atomic Energy Agency chief Mohamed ElBaradei will report the materials' disappearance to the U.N. Security Council later Monday, spokeswoman Melissa Fleming told The Associated Press. "On Oct. 10, the IAEA received a declaration from the Iraqi Ministry of Science and Technology informing us that approximately 350 tons of high explosive material had gone missing," Fleming said. The Iraqis told the agency the materials had been stolen and looted because of a lack of security at governmental installations, Fleming said. "We do not know what happened to the explosives or when they were looted," she told AP. Nearly 380 tons of powerful explosives that could be used to build large conventional bombs are missing from the former Al Qaqaa military installation, The New York Times reported Monday. The explosives included HMX and RDX, which can be used to demolish buildings but also produce warheads for missiles and detonate nuclear weaponry, the newspaper said. It said they disappeared after the U.S.-led invasion of Iraq last year. U.S. President George W. Bush's national security adviser, Condoleeza Rice, was informed of the missing explosives in the past month, the report said. It said Iraq's interim government recently warned the United States and U.N. nuclear inspectors that the explosives had vanished. Before the war, inspectors with the Vienna-based International Atomic Energy Agency had kept tabs on the so-called "dual use" explosives because they could have been used to detonate a nuclear weapon.