BRUSSELS, March 5 (Reuters) - NATO Secretary General Mark Rutte on Thursday welcomed French President Emmanuel Macron's pledge to expand his country's nuclear deterrent but said the U.S. nuclear umbrella would remain the ultimate guarantor of European security.
Macron this week announced France would increase its nuclear arsenal and potentially allow European partners to host French warplanes on deterrence missions, following concerns among allies about the reliability of the U.S..
Rutte said Macron's update to France's nuclear doctrine would make it harder for Russia to assess European deterrence and defense and that he supported discussions over nuclear cooperation between Paris and several European capitals.
But he said Europe could not do without U.S. protection and sought to dismiss concerns over Washington's commitment to defending Europe.
"The ultimate, supreme guarantor of our way of life ... is, in the end, the United States' nuclear umbrella, and that is key," Rutte told Reuters in an interview.
In his speech at a submarine base, Macron said the rethink of French nuclear doctrine had been done in transparency with Washington, and was complementary to NATO's nuclear mission.
France and Germany have established a nuclear steering group to discuss deterrence issues and will start concrete cooperation this year. Greece, Poland, the Netherlands, Belgium, Denmark and Sweden could also be expected to take part in French nuclear wargames, Macron said.
The Trump administration has at times over the past 14 months been scathing in its view of Europe's willingness and ability to defend itself.
In mistakenly shared comments by top Trump administration officials ahead of strikes on Yemen's Iran-aligned Houthis last year, a person identified as Vice President JD Vance wrote "I just hate bailing out Europe", prompting a second official identified as U.S. Defense Secretary Pete Hegseth to lambast European "free-loading" in response.
Under pressure from Washington, NATO's European members have raised their military spending commitments.
A standoff over Greenland earlier this year added to European doubts about U.S. commitments to defending its allies. But Rutte told Reuters he did not doubt the United States' commitment to NATO and the safeguarding of European security.
"I'm absolutely convinced the U.S. is completely committed to NATO," he said.
"The United States knows that to stay safe itself (on) the U.S. mainland, you need a secure Atlantic, a secure Europe, a secure Arctic."
(Reporting by Andrew Gray; Writing by Richard Lough; Editing by Chizu Nomiyama )
