Inspectors from the UN's nuclear agency have arrived in Tehran in an attempt to seal a deal to ease international concerns regarding the country's disputed nuclear programme, state media reports.
Thursday's talks in Tehran are the first between the International Atomic Energy Agency (IAEA) and Iran since August this year.
The ISNA news agency said the seven-member IAEA delegation, headed by Deputy Director General Herman Nackaerts, would meet Iranian nuclear officials behind closed doors during the one-day stop in the capital.
The IAEA says it is seeking to reach agreement with Iran on a "structured approach" to resolve outstanding concerns, and to obtain its inspectors broader access to Iran's nuclear sites and people working in the programme.
The inspectors also want to inspect Parchin, a restricted military complex near Tehran, where the IAEA suspects experiments with explosives capable of triggering a nuclear weapon may have been carried out.
"We also hope that Iran will allow us to go the site of Parchin, and if Iran would grant us access we would welcome that chance and we are ready to go," Nackaerts told reporters at Vienna airport on Wednesday.
ISNA, however, reported that "no inspection or visit" would take place "for now". It did not source the information.
One Vienna diplomat said that the team in Tehran is larger than in past visits in February and in May, and now included two "technical experts" who could conduct verification work at Parchin - if invited to do so.
Iran denies seeking or ever having sought nuclear weapons, and has refused to give the IAEA access to Parchin, saying that as a non-nuclear site the agency has no right to conduct inspections there.
Ramin Mehmanparast, an Iranian foreign ministry spokesperson, said on Tuesday that the visit would focus on discussions regarding "Iran's nuclear rights as well as its peaceful nuclear activities".
But "certain issues that have possibly become a source of concern for [IAEA] officials can also be discussed", he said.