The UN's nuclear watchdog said Friday (October 4th) Iran had taken "a step in the right direction" towards dealing with questions on its nuclear programme but cautioned that the issues have not been "completely addressed", AFP reported.
The International Atomic Energy Agency (IAEA) did not detail what the questions related to but said it was "discussing substance" with the Iranians.
There has been "engagement" from Tehran in recent weeks on questions relating to its nuclear safeguards declarations to the agency, said IAEA acting head Cornel Feruta.
That engagement "does not mean that the issues are completely addressed but it is a step in the right direction", he added.
Feruta said the queries did not touch directly on the faltering 2015 nuclear deal between Iran and world powers but rather on Iran's separate safeguards agreement with the agency.
Diplomatic sources in Vienna say the agency has been waiting for information from the Iranians relating to samples taken earlier this year from a warehouse near Tehran.
At the beginning of September, Feruta had meetings with high-level officials in Tehran and subsequently urged Iran to "respond promptly" to the IAEA's questions, adding: "Time is of the essence."
On Friday, he said the IAEA had "been having a very active dialogue with Iran at both technical and higher levels in the past few weeks".
The latest developments come a week after the IAEA reported that Iran had started using advanced models of centrifuges to enrich uranium, a fresh breach of the 2015 deal.