The UN nuclear watchdog will "work hard" to resolve differences with Iran over its nuclear programme at talks in Tehran, the body's chief inspector said on Tuesday.
"Differences remain... we will work hard to try to resolve these differences," Herman Nackaerts of the International Atomic Energy Agency (IAEA) told journalists at Vienna airport as he boarded a plane for Tehran.
"We will have good negotiations."
IAEA representatives are meeting with Iranian officials on Wednesday in the eighth round of talks in a year.
The agency's goal, Nackaerts said, "is to finalise the structured approach document" which "must facilitate the resolution of the outstanding issues related to the possible military dimension of Iran's nuclear programme".
The IAEA wants Iran to grant it access to nuclear sites, as well as people and documents that can help provide information on its November 2011 report into Tehran's nuclear activities.
In the report, the IAEA said it had credible information that Iran had worked to develop nuclear weapons before 2003 and possibly again since then.
Tehran insists that its nuclear programme is for peaceful purposes.
The IAEA particularly wants to see the Parchin site near Tehran, where it is thought Iran removed evidence of past suspected weapons research activities.