French President Emmanuel Macron has said he stands by comments he made three weeks ago when he described Nato as “brain dead”.
He said members of the alliance needed a “wake-up call” as they were no longer co-operating on a range of key issues.
Allies said at the time they disagreed with his assessment.
German Chancellor Angela Merkel said Mr Macron “used drastic words” and said she did not think “such sweeping judgements are necessary”.
Mr Macron has been at the forefront of moves to boost defence co-operation among European countries.
He has also criticised Nato’s failure to respond to the offensive by Turkey – also a Nato member – in northern Syria.
The Nato alliance was established at the start of the Cold War to bolster Western European and North American security.
What did the French president say?
Mr Macron was speaking at a news conference with Nato Secretary General Jens Stoltenberg, a week before alliance leaders meet in the UK for its 70th anniversary.
“I totally stand by raising these ambiguities because I believe it was irresponsible of us to keep talking about financial and technical matters given the stakes we currently face,” he said.
“A wake-up call was necessary. I’m glad it was delivered, and I’m glad everyone now thinks we should rather think about our strategic goals.”
He said Nato needed to clarify who or what the alliance stood against, adding that he disagreed that Russia or China were the enemies.
“I want a discussion between allies on a concrete commitment to the fight against terrorism in the Sahel and the Middle East,” he said.
Mr Macron was speaking two days after 13 French soldiers were killed in a helicopter collision during an operation against jihadists in Mali.
On Turkey, he said that Ankara could not expect solidarity from Nato allies while launching its Syria offensive as a “fait accompli”.
In the original interview with the London-based Economist, he said European members had to “reassess the reality of what Nato is in the light of the commitment of the United States”.
The French leader urged Europe to start thinking of itself as a “geopolitical power” to ensure it remained “in control” of its destiny.
What’s the issue with Nato?
President Donald Trump’s abrupt decision to pull most US forces out of north-eastern Syria in October took European Nato members by surprise.
The move opened the way for Turkey to push into Syria and create what it termed a security zone along its border. Kurdish forces, who had been helping the US fight the Islamic State (IS) group, were expelled from the area.
Mr Trump has frequently accused European Nato members of failing to provide their fair share of military spending and for relying too heavily on the US for their defence.
How did Nato come about?
The North Atlantic Treaty Organisation was created in 1949 to counter the threat from the Soviet Union as the Communist country sought to expand its power in Europe.
The Soviet Union, an ally in World War Two against Nazi Germany, became an adversary of the West during the Cold War.
It set up its own Warsaw Pact military alliance, including the then Communist countries of eastern Europe, in 1955.
That alliance was dissolved shortly before the collapse of the Soviet Union in 1991 and former Warsaw Pact countries, though not Russia, became Nato members in the years following.
Originally set up to promote “stability and well-being in the North Atlantic area”, Nato was faced with finding a new purpose after the demise of the Soviet Union.
From the mid-1990s, Nato forces were deployed on missions in the former Yugoslavia, launching air strikes to push Serbia out of Kosovo, and in Afghanistan, where the alliance took control of peacekeeping operations.
But as Nato has expanded, it has struggled to overcome Russian concerns that the alliance poses a threat on its borders.