Iran has answered the majority of questions on its nuclear past, but outstanding answers regarding alleged studies on weaponization issues remain a "matter of serious concern," the United Nations nuclear watchdog said Friday, as the UN Security Council engaged in talks about a third sanctions resolution against Iran, according to dpa. "The one major remaining issue relevant to the nature of Iran's nuclear programme is the alleged studies on the green salt project, high explosives testing and the missile re-entry vehicle," the International Atomic Energy Agency (IAEA) said in a confidential report released to its board member states. "This is a matter of serious concern and critical to an assessment of a possible military dimension to Iran's nuclear programme," the report added. In a statement released after the report was circulated, IAEA Director General Mohamed ElBaradei said IAEA inspectors had found no indication that the weaponization studies were linked to nuclear material. "So that gives us some satisfaction but the issue is still critical for us to be able to come to a determination as to the nature of Iran's nuclear programme," he said. The IAEA showed documentation on the issue made available by member states to Iran, the 11-page report said. "This is the way we can ascertain if there is a military dimension in Iran's current or past programme," a senior IAEA official said. But now, the "ball was in the corner of Iran." Iran maintained the allegations were "baseless" and the documentation fabricated. As of February 14, Tehran stressed that this was its final assessment of this point, the report, obtained by Deutsche Presse-Agentur dpa, said. Iran was invited to comment, but "this has not happened yet," the official said. Iran responded to questions regarding the work plan on clarifying its nuclear past. The IAEA found that Iran's declarations were "consistent with its findings" in the case of polonium-210 experiments and the Ghechin uranium mine south of Tehran. Issues on uranium contamination and procurement activities could also be clarified. Overall "quite good progress" has been made, ElBaradei said. "We have managed to clarify all the remaining outstanding issues, including the most important issue, which is the scope and nature of Iran's enrichment programme" he said, Due to Iran's cooperation, the IAEA had a "clearer picture" of Iran's current activities, which however remained not sufficient unless Iran implemented the Additional Protocol, granting snap inspection rights to IAEA inspectors, the Egyptian-born director general warned. Officials were more cautious, saying that Iran had been "somewhat more open" in the past months but additional information was still needed. Tehran, however, continued to defy UN Security Council demands to halt uranium enrichment and forged ahead with its enrichment campaign and also started testing a new, advanced generation of enrichment centrifuges, the IAEA confirmed. In New York, Security Council members began debate over a third sanctions resolution on Iran, tabled by France and Britain. The draft resolution that meets the approval of all five permanent council members, foresees a stricter travel ban for Iranians involved in the nuclear programme as well as further trade limitations and putting activities by Iranian banks under closer scrutiny.