Iran on Monday demanded US guarantees it will never again pull out of the 2015 nuclear accord and warned Tehran will not accept any partial return to the deal.

Washington "must guarantee that no other American government can flout the world or international law, and that what was done will never be repeated," foreign ministry spokesman Said Khatibzadeh told a news conference, referring to the 2018 pullout.

Talks to restore the nuclear deal between Iran and world powers are due to resume in Vienna on November 29, after a suspension since June.

Khabtizadeh said Washington must "definitively lift the unjust and illegal sanctions they have imposed following their withdrawal from the nuclear accord".

The spokesman stressed that progress in the negotiations was contingent on the US lifting sanctions.

The US unilaterally pulled out of the deal under president Donald Trump and reimposed harsh sanctions on Iran, including a unilateral ban on its oil exports.

In response, Iran began in 2019 walking back on strict curbs on its nuclear activities under the deal.

Unless the sanctions are lifted, Iran will not reverse its "compensatory measures", Khabtizadeh said.

President Joe Biden took over the White House in January hoping to return to the 2015 agreement.

There can be no partial return to the deal, the foreign ministry spokesman warned.

"Either we agree on everything or we agree on nothing," he said.

He announced Deputy Foreign Minister Ali Bagheri would serve as Iran's chief negotiator, and visit London, Paris, Berlin and "perhaps Madrid" this week.

On Saturday, Iran's Foreign Minister Hossein Amir-Abdollahian called on the West to be "realistic" and refrain from "excessive demands" on Iran, during a call with his Russian counterpart Sergei Lavrov.