"We had constructive discussions and made some important steps and we will continue discussions in coming weeks," he told reporters at the end of three rounds of talks with Iranian nuclear officials.

"The atmopshere was very good," he added.

The IAEA delegation, including legal, political and technical officials, met with deputy national security chief Javad Vaeidi during his two-day trip.

Iran was slapped with two sets of UN sanctions over its failure to freeze uranium enrichment, but President Mahmoud Ahmadinejad remained defiant, saying on Wednesday that Tehran would never give up its "right" to nuclear technology.