In telephone talks on Monday, Macron urged Raisi to engage in a "constructive manner" in the talks that resumed after a suspension of almost half a year, following the election of the hardliner to the Iranian presidency.

European powers are seeking to revive the Joint Comprehensive Plan of Action (JCPOA) that has been moribund since the United States walked out in 2018, prompting Tehran to ramp up nuclear activities as Washington reimposed sanctions.

France's objective "was to see Iran return to full respect for all of its commitments under the JCPOA and that the United States return to the agreement," the French presidency said.

Macron also "underscored the need for Iran to engage constructively in this direction so that the exchanges allow a swift return to the agreement," it added.

"Iran must return without delay to compliance with all its commitments and obligations... and quickly resume cooperation that allows the (UN atomic) agency to fully carry out its mission," it said.

A statement from Raisi's office added that he urged Macron "to strive with other parties in Vienna to conclude the negotiations and lift the sanctions against Iran."

"Sending a full team to the talks shows Iran's serious will in these talks," Raisi said.

Referring to the United States, he added: "Those who have started to violate the nuclear deal must gain the confidence of the other party for the negotiations to proceed in a real and fruitful manner."

The EU chair of the talks, Enrique Mora, said after the first session of discussions Monday that he felt "extremely positive," though he acknowledged that "difficult issues" have yet to be tackled.