Macron, who spoke from France's Ile Longue nuclear submarine base, updated the country's nuclear doctrine as Russia's war against Ukraine grinds into a fifth year and NATO allies worry about Washington's wavering commitment.

He spoke after the launch of US and Israeli attacks against Iran in a campaign that risks destabilising the Middle East.

"We must strengthen our nuclear deterrent in the face of multiple threats, and we must consider our deterrence strategy deep within the European continent, with full respect for our sovereignty," Macron said.

He announced "the gradual implementation of what I would call advanced deterrence".

"An upgrade of our arsenal is essential," he added. "That's why I ordered an increase in the number of nuclear warheads in our arsenal."

France holds the world's fourth-largest nuclear arsenal, estimated at around 290 warheads.

Macron said eight European countries had agreed to participate in the "advanced" nuclear deterrence scheme proposed by France, including Germany, Britain and Poland.

The countries -- also involving the Netherlands, Belgium, Greece, Sweden and Denmark -- will be able to host French "strategic air forces", which will be able to "spread out across the European continent" to "complicate the calculations of our adversaries", he said.

The scheme could also involve "the conventional participation of allied forces in our nuclear activities," such as recent military exercises in which British forces were involved, Macron added.

The Ile Longue base is home to France's four ballistic missile submarines -- Le Triomphant, Le Temeraire, Le Vigilant and Le Terrible.

At least one is out at sea at any one time to ensure nuclear deterrence.