Iran said it will not allow inspections to be conducted at its facilities beyond those stipulated in the 2015 nuclear agreement, nuclear chief Mohammad Eslami said on Wednesday.
Iran is waiting for the US to respond to a proposal to revive the agreement, from which the US withdrew in 2018.
"We are committed to inspections in the framework of the nuclear deal that are linked to nuclear restrictions which we have accepted in the past ... not one word more, not one word less," said Mr Eslami, who heads Iran's Atomic Energy Organisation.
After the US response to Iran's comments on the draft proposal, another round of talks will take place in Vienna to finalise a potential agreement, AP reported.
On Monday, a senior US official told Reuters that Iran had abandoned some of its main demands for resurrecting the deal, including insisting that international inspectors end some of their investigations into Iran's nuclear programme.
Iran has called for further sanctions relief for reviving the deal, which would entail curbing the country's nuclear capabilities.
Domestically, US President Joe Biden is facing pressure, especially after Iran was accused of attempting to assassinate former US national security adviser John Bolton.
US officials have told reporters that the latest draft of the deal does not include a clause that would remove Iran's Islamic Revolutionary Guard Corps from its list of foreign terrorist organisations, contrary to Iran's demands.
Separately, the UN's International Atomic Energy Agency (IAEA) nuclear watchdog unanimously passed a resolution criticising Iran for traces of unexplained uranium found at three undeclared sites by nuclear inspectors.
Iran blames "dissidents" and Israel for the traces.
In response to the resolution, Iran expanded further its underground uranium enrichment by installing cascades of more efficient advanced centrifuges and also by removing essentially all the IAEA's monitoring equipment installed under the 2015 deal.