Iran continues to cut its most sensitive nuclear stockpile by more than 80 percent in implementing a milestone nuclear deal with six world powers, and is cooperating with the UN nuclear agency to provide greater transparency of its nuclear plan, a UN confidential report showed on Friday. A monthly updating confidential report of International Atomic Energy Agency (IAEA), obtained by Xinhua, showed Tehran has been curbing its disputed nuclear activities under the landmark Geneva deal agreed in last November since the pact came into force on Jan. 20. The report said Iran has cut the amount of its 20 percent enriched uranium by more than 80 percent by diluting or feeding the nuclear stockpile into the conversion process during the past four months, which amounted to 209 kg when the deal took effect. "Iran's stock of UF6 enriched up to 20% U-235 has decreased from 209.1 kg to 38.4 kg," IAEA noted in the document. The 20 percent uranium enrichment is seen as one of the most controversial elements in Iran's nuclear plan, as the nuclear fuel could be used in producing a nuclear weapon if further enriched. Experts say making a nuclear bomb needs at lest around 240 kg 20 percent enriched uranium. Western states suspect Tehran was heading for an atomic weapon secretly under the cover of its civilian nuclear plan, and want Iran to significantly scale back its nuclear program to address western concerns. However, Iran insists the allegation is baseless and forged, saying it would never abandon its nuclear right in seeking peaceful nuclear plan. Under the Geneva interim deal agreed last November between Iran and the so called P5+1 group (Britain, China, France, Russia, the United States plus Germany), Iran would freeze some controversial nuclear activities in six months in exchange for a limited easing of western sanctions on the oil-depending nation's economy. The landmark pact is designed to buy time for negotiations on a final, long-term solution for the decade-old dispute over Tehran's nuclear plan. The IAEA is playing a pivotal role in monitoring whether Iran is complying with deal, helping to rebuild international confidence in resolving the matter through diplomacy. The confidential report also noted progress has been made in the clarification of unresolved issues of Iran's nuclear program as Iran has implemented the seven practical measures to improve the transparency of its atomic plan, including providing information of the "Exploding Bridge Wire (EBW) detonators", the first items of 12 identified possible military dimension issues (PMD) in Tehran's nuclear programe, to the agency. "Iran showed information to the Agency that simultaneous firing of EBW was tested for a civilian application. This is the first time that Iran has engaged in a technical exchange with the Agency on this or any other of the outstanding issues related to possible military dimensions to Iran's nuclear programme since 2008," the report said. EBW detonators could be used in developing nuclear weapon but also has other civilian applications. The UN nuclear watch dog is still assessing the EBW detonators information given by Tehran. In a November 2011 IAEA report, the UN nuclear agency said it had got "credible" information that Iran might have carried out nuclear weapon research secretly. IAEA and Iran struck a deal last November, under which Iran pledged to cooperate with the agency, providing greater transparency of its nuclear plan. The IAEA-Iran talks are separate from the negotiation track between Tehran and the P5+1 group. But U.S. officials say it is vital for Iran to resolve the IAEA's concerns if Tehran is to strike a long-term deal with the six world powers on its nuclear plan by a deadline of July 20.