International Atomic Energy Agency (IAEA) chief Rafael Grossi said on Saturday that reviving the 2015 nuclear deal between Iran and world powers will not be possible without first settling Tehran's issues with the agency.
Iran's nuclear chief Mohammad Eslami told a joint news conference in Tehran with Grossi that outstanding issues would be resolved toward the end of June.
Tehran has agreed to "present documents to the IAEA to close remaining issues", he said.
Tehran and Washington have held more than 11 months of indirect talks in Vienna on reviving the pact, which was abandoned in 2018 by former US President Donald Trump, who also reimposed far-reaching sanctions on Iran.
The 2015 deal limited Iran's enrichment of uranium, to make it harder for Tehran to develop material for nuclear weapons, in return for a lifting of economic sanctions.
All parties involved in the talks aimed at bringing Tehran and Washington back into compliance with the nuclear pact have said they were close to reaching an agreement in Vienna.
One wildcard is an effort by the IAEA to resolve questions about nuclear material that the Vienna-based agency suspects Iran failed to declare Grossi said there are matters that still need to be addressed by Iran.