"The announcements by Iran... go against the Vienna agreement," the French foreign ministry said in a statement after President Hassan Rouhani said Iran would resume enrichment at the Fordow plant.

"We urge Iran to go back on its decisions which contradict the accord," it added.

French President Emmanuel Macron has led efforts to salvage the 2015 nuclear deal between Iran and world powers, severely damaged by the decision in May 2018 of US President Donald Trump to walk out of the accord.

Macron has notably tried to broker a historic face-to-face between Trump and Rouhani but the idea is yet to gain momentum. The latest announcements from Tehran risk setting back even further the diplomatic efforts to solve the standoff.

The French foreign ministry statement said that it was "deeply worried" by Iran's latest steps and would await reports from the UN nuclear agency on the Iranian actions.

It said France remained committed to the nuclear deal and urged Iran to adhere to its obligations and fully cooperate with the UN's nuclear agency.

"France remains entirely engaged to work for a deescalation of tensions. A return to full compliance with the accord is one of the key objectives of this process," it said.