Speaking from the Ile Longue nuclear submarine base as the clock ticks on his presidency, Macron announced that eight European countries including Germany, Poland, Sweden and Britain had agreed to participate in what he called a "forward" nuclear deterrence scheme.

In a joint statement following Macron's speech, France and Germany said they had set up a "nuclear steering group", saying such an arrangement would "add to, not substitute for, NATO's nuclear deterrence".

"We are currently experiencing a period of geopolitical upheaval fraught with risks," Macron said, speaking 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 eight European countries had agreed to join his plan to use France's nuclear stockpile to bolster security on the continent.

The countries -- including the Netherlands, Belgium, Greece and Denmark -- will be able to temporarily 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 have been involved, Macron added.

He stressed that France would maintain tight control over nuclear decision-making.

In the joint statement, France and Germany said they had agreed to take "first concrete steps beginning this year", including German conventional participation in French nuclear exercises.

- 'Arming up with our friends' -

Macron updated France's nuclear doctrine as Russia's war against Ukraine grinds into a fifth year and NATO allies worry about Washington's wavering commitment to Europe.

Reassurances from US officials that the American deterrent would continue to cover Europe under the NATO alliance have done little to quell European fears of fickleness under US President Donald Trump.

Macron stressed the new effort would be "in addition to NATO's nuclear mission".

"The forward deterrence we are proposing is a separate effort, which has its own value and is fully complementary to NATO's, both strategically and technically," he said.

He also said he ordered an increase in the number of nuclear warheads, but added France would no longer be disclosing any details on its stockpile.

Macron listed the measures as France's allies fret that a possible win by the eurosceptic far-right National Rally party of Marine Le Pen in next year's presidential election could undermine European cooperation.

Polish Prime Minister Donald Tusk said Poland was in talks with France and other European allies on further steps. "We are arming up together with our friends so that our enemies will never dare to attack us," he said on X.

Swedish PM Ulf Kristersson also said his country viewed Macron's initiative "positively".

"Naturally, we would most like to see a world completely free of nuclear weapons," he said.

"But as long as Russia has these weapons and threatens its neighbours, democracies must be able to deter attacks and safeguard our own security and freedom."

- Electoral politics -

France maintains the world's fourth-largest nuclear arsenal, with around 290 warheads. Britain, which is no longer a member of the EU, is the only other European nuclear power.

By contrast, the US and Russia, the world's two main atomic powers, each have thousands of nuclear warheads.

Rafael Loss, a policy fellow at the European Council on Foreign Relations, warned that a far-right electoral victory next year "could walk back many or even most of these steps".

"Macron emphasised that France would not share decision-making authority and that it would not conduct joint planning of nuclear operations with European partners -- suspicions that the French fringes harbour as undermining French sovereignty," he told AFP.

"Still, electoral politics can have a great impact on the credibility of nuclear deterrence as perceived by allies and adversaries -- as developments since Trump's re-election demonstrate."