Iran has agreed to give International Atomic Energy Agency inspectors access to two suspected former nuclear sites.
A joint statement said Iran was doing so in good faith to resolve outstanding issues related to nuclear safeguards.
The agreement came during a visit to Tehran by the IAEA's director general.
The global watchdog has criticised Iran for not answering its questions about possible undeclared nuclear material and nuclear-related activities at the two locations, and denying it access.
