"I don't see any possible consensus," Macron said after a NATO summit marred by the spat with Turkey over its demand that allies brand as "terrorists" the Kurdish militias of northeastern Syria that helped a US-led coalition defeat the Islamic State group.

Turkish President Recep Tayyip Erdogan had threatened to block an update to defence plans for the Baltic republics and Poland unless NATO recognised the Syrian Kurdish People's Protection Units (YPG) as terrorists.

After meetings between Erdogan and US President Donald Trump, as well as Baltic and Polish leaders, Turkey dropped its objections, but the fractious mood continued even after the summit ended.

Macron rejected Ankara's assertion that the YPG is an offshoot of the PKK, or Kurdistan Workers' Party, which has waged a long insurgent campaign against the Turkish state and is widely acknowledged internationally as a terror group.

"We do not agree to classify the YPG-PYD as a terrorist group," he told reporters.

"We are fighting the PKK and all those who carry out terrorist activities against Turkey, in a very clear way, but we do not make this shortcut or connection that Turkey wants between these different political and military groups."

France has been angered by Turkey's military operation in northern Syria against the YPG, which was a key ally in the fight against the Islamic State.

On the eve of the summit, Macron accused Turkey of working with IS proxies in Syria during its offensive, which Ankara said was needed to create a "safe zone" to prevent Kurdish attacks on its territory.

After the working session of the summit near London, NATO Secretary General Jens Stoltenberg announced that agreement had been reached on the Baltic defence plan.

Lithuanian President Gitanas Nauseda welcomed the news, thanking Erdogan "for the solidarity", though it was not clear what, if anything, Turkey had got in return for its support.

Macron said he felt a four-way meeting on Tuesday with Erdogan and the British and German leaders had helped "clear up misunderstandings", adding he thought the Turkish leader had concluded blocking the plan was not in his interests.