Iran and the UN's nuclear agency say they have made progress in talks on Tehran's nuclear programme.
The Tehran talks were "constructive" says the IAEA's Olli Heinonen
In July the two sides announced a two-month arrangement aimed at clearing up outstanding questions and giving the agency better access to nuclear sites.
Both now say they have agreed on a timeline for implementation during a fresh round of talks in Tehran.
Western powers suspect Iran of building a nuclear weapons capability. Tehran says its nuclear programme is peaceful.
Olli Heinonen, deputy director of the International Atomic Energy Agency, said the two days of talks had been "good, constructive".
Iranian deputy nuclear negotiator Javad Vaeedi, said: "We have a basic framework of agreement between Iran and the agency."
The UN Security Council has already approved sanctions against Iran, urging it to stop uranium enrichment activities.
Since July's agreement, Iran has allowed the IAEA's inspectors to visit its heavy water research reactor at Arak, and has been holding talks with a UN technical team on guidelines for inspecting its uranium enrichment plant at Natanz.
BBC Iran analyst Pam O'Toole says that over the past few months, Iran has appeared anxious to demonstrate the transparency of its programme.
One Iranian official recently expressed hope that the West could respond to Iran's co-operation with the IAEA by not pushing for more sanctions.
However, some Western analysts have alleged that Tehran is simply trying to play for time, hoping to delay the imposition of further sanctions while it increases its nuclear know-how.