In an interview with British weekly The Economist, Emmanuel Macron said that NATO lacked coordination and suffered from US unpredictability under President Donald Trump.
Macron also expressed doubts about Article Five, NATO’s security maxim that an attack on one ally is an attack on all 29 of the alliance’s member states.
The French president’s words have sparked outrage among NATO diplomats, with one calling the interview stupid and arrogant, public broadcaster Polish Radio’s news agency IAR reported on Friday.
Another diplomat said that NATO members should express their doubts behind closed doors and not in public.
IAR did not name any of the officials it cited.
The Reuters news agency has described Macron's comments, which came a month before NATO's December 4 summit in London, as unexpected and cited German Chancellor Angela Merkel as saying that Macron was overreacting.
"The French president has found rather drastic words to express his views. This is not how I see the state of cooperation at NATO," Merkel told a news conference in Berlin on Thursday.
NATO Secretary-General Jens Stoltenberg told Reuters that NATO had overcome differences in the past, citing the 1956 Suez Crisis and the 2003 Iraq War.