Ayatollah Ali Khamenei said it was not a question of "whether the United States returns or not", it was a matter of it lifting its unilateral sanctions.

"We are in no rush and we are not insisting on their return. Our demand, which is both logical and rational, is the lifting of sanctions" that outgoing US President Donald Trump reimposed after quitting the deal in 2018.

"We are talking about a right which has been stolen from the Iranian nation," Khamenei said in a televised speech.

"If the sanctions are lifted, the return of the Americans makes sense."

Since 2019, Iran has gradually suspended implementation of most of its key obligations under the nuclear deal, which set strict limits on its activities in return for the lifting of sanctions.

Other parties to the agreement, notably Britain, France and Germany, have pressed Iran to return to its commitments in a bid to rescue the deal, but Iran has repeatedly demanded that the United States first lift its crippling sanctions.

"When the other party meets practically none of its obligations, it is not logical for the Islamic republic to honour all of its commitments," Khamenei said.

"If they return to their commitments, we will return to ours."