The head of the UN atomic agency called Monday on Iran to allow immediate access to the Parchin military base where it suspects nuclear weapons research took place, AFP reported.
Yukiya Amano said that this should be granted "without further delay" and without waiting for stalled talks to conclude an agreement on investigating other alleged "weaponisation" activities.
"I request Iran once again to provide access to the Parchin site without further delay, whether or not agreement has been reached on the structured approach," Amano told the International Atomic Energy Agency board of governors meeting.
"Providing access to the Parchin site would be a positive step which would help to demonstrate Iran's willingness to engage with the Agency on the substance of our concerns," he said, according to the text of his remarks at the closed-door gathering.
On Feb. 13 Iranian negotiating team held nuclear talks with IAEA in Tehran. After the negotiations, Iran's representative to IAEA, ambassador Ali Asghar Soltanieh said both sides reached agreements on "some points", however the IAEA inspectors were not granted access to visit the Parchin military complex.
The IAEA, whose mission is to prevent the spread of nuclear weapons, has been trying to negotiate a so-called structured approach with Iran giving the inspectors access to sites, officials and documents for their long-stalled inquiry.
World powers are monitoring the IAEA-Iran talks for any signs as to whether Tehran, facing intensifying sanctions pressure, may be prepared to finally start tackling mounting international concerns about its nuclear activity.
The U.S. and its Western allies suspect Iran of developing a nuclear weapon - something that Iran denies.
The Islamic Republic has on numerous occasions stated that it does not seek to develop nuclear weapons, using nuclear energy for medical researches instead.