Iran says progress has been made at its latest talks with the UN's nuclear watchdog, the IAEA.
Iran's top nuclear envoy, Ali Asghar Soltanieh, said the two days of discussions had been "fruitful".
An IAEA official said talks would resume on Monday after a "good exchange of views".
The agency wants Iran to address concerns over possible military aspects of its nuclear programme. Iran insists it it is purely peaceful.
"The primary focus of our discussions was how to clarify issues related to the possible military dimensions of Iran's nuclear programme," IAEA deputy director-general Herman Nackaerts said after the talks.
"We decided that in order to continue this work towards a conclusion we will have the next round of talks next week," Mr Soltanieh said.
Before the talks on Monday and Tuesday, Mr Nackaerts urged Iran to allow his team to visit a suspect military site at Parchin.
Neither official commented on whether the issue had been discussed at the talks, according to the Reuters news agency.
This meeting comes a week before the next round of talks between six world powers and Iran are scheduled to begin in Baghdad.
The last series of full international talks with Iran broke down in early 2011.
Since then the International Atomic Energy Agency (IAEA) has expressed concern that Iran has failed to co-operate with its inspectors and has carried out activities "relevant to the development of a nuclear explosive device".
Israel believes a nuclear-capable Iran would be a direct threat to its security, and Prime Minister Benjamin Netanyahu has hinted that Israel may attack Iran's nuclear facilities if diplomacy fails.
But US President Barack Obama has warned against "loose talk of war", while stressing that all options remain open.