UN nuclear watchdog says had 'constructive' talks with Iran on two remaining unanswered questions.

UN nuclear watchdog says had 'constructive' talks with Iran on two remaining unanswered questions. (Taz).

The five-member team visiting Iran comprised senior IAEA safeguards officials, including the UN nuclear watchdog's Deputy Director General for Safeguards Tero Varjoranta.

At the time, AEOI Spokesman Behrouz Kamalvandi said the discussions focused on the two remaining issues in Iran's nuclear dossier.

Noting that the IAEA had delayed declaring the results of its analysis of the information sent by Iran about the two recent issues that were mentioned in the third stage of their cooperation agreement, the spokesman said one of these cases was about the alleged initiation of explosives in Marivan, and the other one is related to papers published in Iran in relation to neutron transport and associated modeling and calculations and their alleged application to compressed materials.

"Iran has told them that if they think some explosions have taken place, they should specify its location so that we will give you (controlled) access (to such alleged sites)," Kamalvandi said.

He explained that Iran and the IAEA's step-by-step cooperation was based on this agreement that the two sides could deal with other steps only after finalizing different subjects mentioned in the previous step, and thus, Tehran and the UN nuclear watchdog would not deal with other issues before wrapping up the two aforementioned issues with regard to Marivan and neutron transport case.

The UN nuclear watchdog said on Thursday it had a "constructive exchange" this week with Iran on two issues related to its nuclear program that the agency says Tehran has been failing to fully address since August, Reuters reported.

The International Atomic Energy Agency's (IAEA) investigation runs parallel to talks between Tehran and six world powers that aim to broker a deal by end-June to scale down Iran's nuclear program in exchange for sanctions relief.

The IAEA, which held technical talks with Iranian officials in Tehran on Wednesday, said the two sides would meet again soon, without giving a date.

The IAEA had said it expected progress this month on the two outstanding issues, which are related to the nature of neutron calculations and alleged experiments on explosives that could be used to develop an atomic device.

It has also expected Iran to propose new measures to address other outstanding issues with the IAEA, but the IAEA did not mention any new steps. Iran's IAEA envoy in Vienna did not immediately respond to an email seeking comment.

Diplomats have voiced concern there could be little progress in the IAEA probe until a final political deal is reached. The United States, France, Russia, China, Britain and Germany agreed on a framework deal with Iran on April 2.