Emmanuel Macron has said his claim this month that Nato was “brain-dead” was a necessary wake-up call before a summit in London next week at which he will urge members of the alliance to take a greater interest in its southern flank, including the fight against terrorism in the Sahel.

The French president defended his comments in Paris alongside the Nato secretary general, Jens Stoltenberg, who had previously warned Macron not to expect that a European defence formation could replace the Nato transatlantic structure.

An unrepentant Macron said: “The questions I have asked are open questions, that we haven’t solved yet.”

He said: “Peace in Europe, the post-INF [intermediate-range nuclear forces treaty] situation, the relationship with Russia, the Turkey issue – who’s the enemy? So I say: as long as these questions are not resolved, let’s not negotiate about cost-sharing and burden-sharing or this or the other.”

Macron said he was glad he had lifted the lid on the ambiguities. “A wake-up call was necessary, I’m glad it was delivered and I’m glad everyone now thinks we should think about our strategic goals.”

Greater Nato involvement in the Sahel would be wholly beneficial and the subject should be on the table at the Nato summit next week, he added. Europe’s true common enemy was not Russia or China, but terrorism, he said.

Macron complained that the last two summits had been “devoted solely to working out how we could lighten the financial cost to the United States”, and he criticised the “glaring and unacceptable disconnection” between the discussions about the amount of the US financial contribution and the challenges the alliance was facing.

Although at recent summits Donald Trump has railed against what he regards as Europe’s freeloading, in the run-up to next week’s 70th anniversary summit there have been fundamental divisions about the organisation’s purpose.

Poland and the Baltic states are particularly infuriated at what they regard as Macron’s pro-Russia, anti-US stance.

Macron was also critical of Turkey, saying it could not expect solidarity from Nato allies while launching an offensive in Syria.

Turkey has blocked a Nato defence plan for the Baltics and Poland after some members refused to formally recognise Kurdish fighters in Syria as a security threat.

A meeting between France, Germany, UK and Turkey on the state of the Turkish incursion into northern Syria is likely to happen on the sidelines of the summit.

On Wednesday, Reuters and Turkish media reported that Nato had agreed this year to a collective security guarantee for Turkey in the event of an attack from its southern border with Syria, where since October Ankara has been locked in a battle with Kurdish-led forces previously supported by the US in the fight against Islamic State.

The plan included recognising the People’s Protection Units (YPG), the main component of the umbrella Syrian Democratic Forces (SDF), as a terrorist threat to Turkey. Ankara says the YPG are the Syrian branch of the Kurdistan Workers’ party (PKK), an outlawed group that has waged an insurgency against the Turkish state for decades, and it has long been infuriated by western support for the Syrian groups.

However, worried about a potential legal obligation to fight against a force it supported in Syria, Washington later withdrew its support, leading other countries to oppose it too, Turkish diplomats have alleged. They did not specify when the plan was submitted or when the US withdrew support.

In retaliation, Turkey now says that at next week’s summit it will block formal approval of a military plan to defend Poland, Lithuania, Latvia and Estonia in the event of a Russian attack. Both plans need the backing of all 29 member states.

Turkey’s foreign minister, Mevlüt Çavuşoğlu, confirmed the reports that it had blocked the Baltic plan, telling reporters: “We are not against Nato’s retaliation plans for the Baltic nations but [Nato] should also want for Turkey what it wants for the Baltics.”

In London, the UK foreign secretary, Dominic Raab, said Europe had opposed the Turkish incursion into Syria, but said it would be a strategic blunder if criticism of Turkey drove the country into the arms of Vladimir Putin.

Turkey has defied the Nato alliance and angered the US by purchasing a Russian defence system, a decision that the US says makes it impossible for the US to provide Turkey with military aircraft.

Macron also said France would begin a review of its Barkhane intervention in the Sahel following the death of 13 soldiers in Mali this week, with “all options on the table”.

“In this context, and in light of the decisions that France will take, a bigger engagement by its allies is obviously something that would be quite positive,” he said.

Although Britain has provided helicopters and security personnel to help France’s 4,500-member Barkhane force in west Africa, and the US provides intelligence support, France has so far failed to persuade other allies to make a significant contribution.

“In the Sahel, France is involved and acting on behalf of everyone,” Macron said. “If some people want to see an example of what they term cost-sharing, they can come Monday to the ceremony France is organising” for the dead 13 soldiers. “There they will see the cost.”