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, December 15, 2015. [Photo/Agencies]

VIENNA-- Board members of the United Nations nuclear agency on Tuesday adopted a resolution to close the investigation into whether Tehran once had a nuclear weapons program, upon a review of Iran's implementation of its commitments under a nuclear deal endorsed by the UN Security Council in July.

After a 12-year investigation of Iran's suspected nuclear plans, the International Atomic Energy Agency (IAEA) decided to close the process in light of the historic nuclear deal.

The development marks a positive step towards normalizing Iran's relations with the international community, analysts said.

Upon receipt of the IAEA report by board members verifying Iran's implementation of its relevant commitments under the Joint Comprehensive Plan of Action (JCPOA), the probe of Tehran's past suspected nuclear activities will be finished, according to the resolution.

"All the activities in the roadmap for the clarification of past and present outstanding issues regarding Iran's nuclear program were implemented in accordance with the agreed schedule and further notes that this closes the board's consideration of this item," the resolution noted.

Back in November 2011, IAEA listed 12 areas of possible military dimensions (PMDs) of Iran's nuclear ambitions, noting Tehran might have carried out research and experiments to develop nuclear weapon. However, Tehran always denied the allegations, saying the information was forged and misleading.

An IAEA report issued this month suggested Iran carried out nuclear bomb research before 2003, but found no sign of weapons-related activities beyond 2009.