UN nuclear watchdog officials left Tehran on Monday after talks with the head of Iran's nuclear energy organization, the semi-official ISNA news agency reported, without saying whether they addressed an impasse over uranium traces at undeclared sites.
It said the delegation of the International Atomic Energy Agency, led by its deputy director general for safeguards, Massimo Aparo, held negotiations with Iranian teams and met Mohammad Eslami, head of Iran's Atomic Energy Organisation.
The two sides exchanged views on "future joint cooperation and programs, in addition to safeguarding issues", ISNA said.
Speaking last week, Eslami said he hoped the visit could help resolve outstanding issues between the two sides.
The IAEA said last year Iran had failed to explain traces of uranium found at several undeclared sites, which the agency said affected its ability to say whether Iran's nuclear work was part of a peaceful energy project, as Tehran has always maintained.
The issue has been an obstacle to progress in wider talks to revive the 2015 Iran nuclear deal with major powers to curb its disputed uranium enrichment programme in return for lifting sanctions imposed by Washington after exiting the pact in 2018.