Tensions have soared in the Gulf in the last weeks as Iran ramped up its controversial nuclear programme following the US pullout from a 2015 deal on Iran's atomic drive signed by world powers in Vienna.

Le Drian told the French parliament he had met Deputy Foreign Minister Abbas Araghchi, who Iranian media said brought an unspecified message from President Hassan Rouhani for French counterpart Emmanuel Macron.

"We are now pushing Iran to return to the Vienna agreement," Le Drian said. "I met earlier with President Rouhani's special envoy to tell him that."

Paris has engaged in intense diplomacy to seek to solve the current escalation diplomatically, with Macron's foreign policy advisor Emmanuel Bonne twice visiting Tehran.

In a ramping up of tensions, Iran seized the British-flagged tanker Stena Impero on Friday in the Gulf's strategic Strait of Hormuz.

"We need to put in place as process of de-escalation to reduce the tensions," said Le Drian.

He also said Britain, France and Germany were working on an observation mission for the Gulf. British Foreign Secretary Jeremy Hunt on Monday said a European-led protection force was planned for shipping in the Gulf.