International Atomic Energy Agency (IAEA) Director General Yukiya Amano addresses a news conference after a board of governors meeting at the IAEA headquarters in Vienna, Austria, November 26, 2015.

The UN nuclear agency found no credible evidence which indicates Iran carried out nuclear bomb plan after 2009 and delivery system research after 2011, according to the confidential final assessment report from the agency seen by Xinhua on Wednesday.

The final 16-page confidential report released by the International Atomic Energy Agency (IAEA) to its board members said based on its investigation and cooperation of Iran, IAEA assesses that Tehran has carried out activities relevant to the development of a nuclear explosive device before 2003 while some activities took place after 2003, the report said, but saying the activities did not go into practices.

"A range of activities relevant to the development of a nuclear explosive device were conducted in Iran prior to the end of 2003 as a coordinated effort, and some activities took place after 2003. ......, the Agency has no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009," the report said.

In the November 2011 IAEA report, the agency specified 12 areas of Iran's suspicious nuclear plan relevant to the atomic weapon program, the so called possible military dimensions (PMDs), which Tehran denies.

The IAEA final report of Iran nuclear program indicates Iran has not carried out nuclear bomb research plan since 2009 while the agency found no credible evidence of delivery system development since the 2011 report.

"The Agency has verified the existence in Iran of two of the workshops referred to in the alleged studies documentation on the integration into a missile delivery vehicle, but has not received any other information on this area since the 2011 Annex," the report said.

The delivery system is also a key element of the nuclear weapon program, as the nuclear warhead need to be delivered by missile to the target.

IAEA and Tehran signed a "Road-map" in July to clarify Iran's past nuclear unresolved PMD issues in accordance with the historic Iranian nuclear deal.

The report said Iran, in cooperation with IAEA, have implemented all the activities contained in the Road-map by deadline.

Iran's ambassador to the International Atomic Energy Agency (IAEA) Reza Najafi addresses the media after a board of governors meeting at the IAEA headquarters in Vienna March 4, 2015.

"Iran provided explanations in writing and related documents on past and present outstanding issues, ......, the Agency conducted safeguards activities at particular locations of interest to the Agency, including at the Parchin site," the report noted.

The report seems to give some conclusion based on the information the IAEA got and the investigations carried out, however, IAEA chief Yukiya Amano last week said that the final assessment would not deliver a "yes or no" answer to the question whether Tehran has carried out nuclear weapon plan.

One of the key issues, the suspected Parchin military site of Iran which is suspected to have carried out explosive experiment relevant to the nuclear bomb research plan, is also mentioned in the report.

IAEA said the cylinder installed in the Parchin site matched the parameters of an explosives firing chamber. However, IAEA failed to conduct effective verification as Iran undertook "extensive activities" since February 2012 at the site.

Iranian Deputy Foreign Minister Abbas Araghchi said Wednesday that all Iran's work was conducted for peaceful goal, according to the Islamic Republic News Agency report, saying the UN nuclear agency should close the book on the question of Iran's nuclear past within two weeks, he added, allowing implementation of the nuclear deal to move forward.

A Vienna based diplomat believed the report might not have great negative effect on the implementation of the Iranian nuclear deal, and the IAEA board members states are supposed to discuss the report and adopt a resolution on Dec. 15.