Iran reaffirmed Monday its "readiness" to cooperate with the UN nuclear watchdog, after the agency said in a report it "cannot assure" the peaceful nature of Tehran's nuclear programme.

The finding last week by the International Atomic Energy Agency (IAEA) further complicated diplomatic efforts to revive a landmark 2015 nuclear deal between Iran and major powers, including the United States.

Iran is "ready to cooperate with the agency to clear up the false and unrealistic perceptions regarding its peaceful nuclear activities", foreign ministry spokesman Nasser Kanani said in a press conference.

Tehran declares its "readiness to continue constructive cooperation with the IAEA", Kanani added, also pointing to the agency's "obligations".

In its report last Wednesday, the IAEA said it was "not in a position to provide assurance that Iran's nuclear programme is exclusively peaceful".

The IAEA has been pressing Iran for answers on the previous presence of traces of nuclear material at three undeclared sites. The issue led to a resolution criticising Iran being passed at the June meeting of the IAEA's board of governors.

Tehran, which has consistently denied seeking nuclear weapons, responded to the resolution by disconnecting 27 cameras allowing the agency to monitor some of its nuclear activities.

The IAEA board met again in Vienna on Monday for its quarterly meeting.

"To our knowledge, no draft resolution has been submitted for this meeting," Kanani said.

Any further "unconstructive action" by the agency, Kanani said, "will again have unconstructive results".

Tehran has demanded that the IAEA's probe be concluded as part of any deal -- one of the sticking points in the talks to restore the 2015 agreement that gave Iran much-needed relief from sanctions in return for curbs on its nuclear programme.

The United States unilaterally withdrew from the deal in 2018 under then-president Donald Trump, reimposing biting economic sanctions that prompted Iran to begin rolling back on its own commitments.

Last month, the European Union put forward a "final" draft of the agreement to lift sanctions on Tehran once again and push Iran to fully comply with its obligations.