Iran needs to provide substantive explanations regarding nuclear weapons studies it is alleged to have carried out, the International Atomic Energy Agency (IAEA) said Monday, dpa reported.
The weaponization issues regarding uranium conversion, high explosives testing and design of a missile re-entry vehicle remained a "matter of serious concern," the UN nuclear watchdog said in a confidential report forwarded to its 35 board-member states.
"Substantive explanations are required from Iran to support its statements on the alleged studies and on other information with a possible military dimension," said the report, a copy of which was obtained by Deutsche Presse-Agentur.
Diplomats in Vienna said they believed Iran could provide the necessary information. "We have not gotten substantive answers and I think we could have gotten those earlier," a senior UN official said.
Now it was up to the IAEA board and Iran to take the next steps, he added. Iran provided the IAEA with further information on May 23, which was currently being assessed.
Clarification by Iran on those issues as well as the role of a document showing procurement activities of military-related institutions and the production of uranium metal hemispheres - an application solely for nuclear weapons, were required to assess the nature of the programme, the report said.
The information, "which was provided to the agency by several member states, appears to have been derived from multiple sources over different periods of time, is detailed in content and appears to be generally consistent," said the report, which will be discussed at the IAEA's upcoming board meeting starting on June 2.
Tehran, while not disputing that information contained in the documents was factually accurate, insisted the information made available to the IAEA by several member states was "baseless and that the data have been fabricated." Events and activities concerned involved civil or conventional military applications, Iran said.
Iran continues to defy UN Security Council demands to halt uranium enrichment and is currently operating around 3,500 centrifuges, enriching uranium to about 4 per cent, not enought to make weapons.
By the end of the summer, Iran will have a total of 6,000 centrifuges installed, senior UN officials said, indicating that progress was not as fast as claimed by Iran.
Tehran, which kept its nuclear programme hidden from IAEA inspectors for 18 years, maintains it is geared solely towards energy production.