Iran will not accept the United Nations nuclear watchdog's "excessive" demands, the spokesperson of the country's Atomic Energy Organisation (AEOI) said on Tuesday.
A report by the semi-official Tasnim news agency cites Behrouz Kamalvandi to say it is not possible to implement IAEA's demands.
"We consider the IAEA's demands excessive, because their implementation is impossible due to sanctions," Tasnim quotes Kamalvandi.
"If they lift sanctions ... then Iran will reciprocate," he added.
After months of indirect talks, Tehran and Washington are engaged in talks to revive a 2015 nuclear deal.
Iran's President Ebrahim Raisi however said on Monday IAEA's investigation into "safeguards issues", relating to nuclear particles found at Iranian nuclear sites, needs to end if any deal is to be struck.
The Joint Comprehensive Plan of Action (JCPOA) introduced curbs on Iran's nuclear programme in exchange for lifting sanctions.