Iran's supreme leader Ali Khamenei waves to the crowd during an event held in Tehran on Wednesday on the occasion of the 41st anniversary of the victory of the Islamic revolution which toppled the monarchy in 1979. Photo: AFP

Iran's Supreme Leader Ayatollah Ali Khamenei said on Sunday that Tehran's "final and irreversible" decision was to return to compliance with the 2015 nuclear deal only if Washington lifts sanctions on the Islamic Republic, Iranian state TV reported.

The comment, as well as US President Joe Biden's separate statement that the US would not lift sanctions simply to get Iran back to the negotiating table, appeared to be posturing by both sides as they weigh whether and how to revive the pact.

The deal between Iran and six major powers limited Iran's uranium enrichment activity to make it harder for Tehran to develop nuclear arms - an ambition Iran has long denied having - in return for the easing of US and other sanctions.

But former US president Donald Trump abandoned the deal in 2018, denouncing it as one-sided in Iran's favor, and reimposed sanctions that have crippled Iran's economy.

"Iran has fulfilled all its obligations under the deal, not the United States and the three European countries ... If they want Iran to return to its commitments, the United States must in practice ... lift all sanctions," state TV quoted Khamenei as saying during a meeting with Air Force commanders.

"Then, after verifying whether all sanctions have been lifted correctly, we will return to full compliance ... It is the irreversible and final decision and all Iranian officials have consensus over it."

While Iran has insisted the US first drop its sanctions before it resumes compliance, Washington has demanded the reverse.

In a segment of a CBS News interview broadcast on Sunday, Biden said "no" when asked whether Washington would lift sanctions to get Tehran to the negotiating table.

Asked if Iran had to stop enriching uranium first, Biden nodded. It was not clear exactly what he meant, since Iran was allowed to enrich uranium to 3.67 percent under the deal, known as the Joint Comprehensive Plan of Action.

Reuters