The U.N. nuclear watchdog said it had a "constructive exchange" with Iran this week but there was no sign of a breakthrough on aspects of its nuclear program that the agency says Tehran has failed to fully address.
The International Atomic Energy Agency (IAEA) is investigating Iran's nuclear program in parallel to talks between Tehran and six world powers that aim to broker a deal by the end of June to scale down the program in exchange for sanctions relief.
In any final deal, the IAEA would play a major role in monitoring Iran's compliance.
The IAEA said in March it expected progress with Iran this month on outstanding issues related to the nature of neutron calculations and alleged experiments on explosives that could be used to develop an atomic device.
It said then it expected Iran to propose new measures to address other outstanding issues with the IAEA by mid-April.
The IAEA on Thursday issued a short statement saying it had technical talks with Iranian officials in Tehran on Wednesday, making no mention of major developments.
"The two sides ... had a constructive exchange on the two practical measures under discussion," it said. "The Agency and Iran will continue this dialogue and agreed to meet again in the near future."
Iran's envoy to the Vienna-based IAEA did not respond to an email seeking comment.
The United States, France, Russia, China, Britain and Germany agreed on a framework deal with Iran on April 2. The powers and Iran will meet again in Vienna next week.
Iranian Defense Minister Hossein Dehghan said on Thursday he hoped Iran's work with the IAEA would help it work out a final agreement.
