President Macron has aired the idea that France's deterrence force could be used to defend of other European countries.

European leaders showed a cautiously receptive ear to President Emmanuel Macron's proposal to debate extending the French nuclear umbrella to Europe on Thursday, though some were reluctant to draw a line under years of U.

"In the current situation, the French and British nuclear forces are a complement to U.S. extended deterrence, but they would not constitute a viable solution in the event of an abrupt withdrawal of U.S. nuclear forces," the Washington-based Centre for Strategic & International Studies said.

Emmanuel Macron has proposed opening a dialogue with other European countries on France's nuclear deterrent, raising questions about what a French nuclear umbrella over Europe might entail –

The UK and France are among five internationally recognised nuclear powers. The UK has "assigned" its nuclear capabilities to any other NATO country should it come under nuclear attack.

European leaders on Thursday responded cautiously but receptively to President Emmanuel Macron’s proposal to debate extending the French nuclear umbrella to Europe. Some leaders, however, were reluctant to abandon decades of US protection.

With U.S. security commitments in question, discussions grow around France’s nuclear deterrence strategy for the continent.