Macron spars with US and Turkey over Nato

"We can't put money and pay the cost of our soldiers' lives without being clear on the fundamentals of what Nato should be," he said.

The position follows his earlier comments describing Nato as "brain dead", given Turkey's October invasion into north-east Syria, displacing tens of thousands of people.

After US president Donald Trump abandoned the Kurdish militias, who had fought alongside US and French troops in the struggle against the Islamic State, Turkey moved in.

Trump's move - leaving the Kurdish militias exposed to Turkish troops and rocket fire - in turn triggered an international and domestic backlash.

Ankara insists the Kurdish militia are terrorists and wants to carve out a so-called safe zone in the area, where it then wants to push back Syrian refugees currently hosted in Turkey.

But the safe-zone idea has received no support from a European Union that is increasingly wary of Turkey's president Recep Tayyip Erdogan using refugees as political and strategic leverage.

Meanwhile, Turkey had earlier threatened to block Nato efforts to better secure the Baltic republics against any possible Russian aggression.

The threat followed Turkey's controversial purchase of the Russian S-400 air defence system. Fears are mounting that a Russian air defence system inside Nato could expose sensitive information to Russian military intelligence.

But Lithuanian foreign minister Linas Linkevicius had down played Erdogan's Baltic threat, telling EUobserver it was more about Turkey flexing its muscles than substance.

Erdogan insists the alliance members must first recognise the Kurdish militias in Syria, also known as the YPG, as terrorists.

Macron on Tuesday baulked.

"The common enemy today are the terrorist groups, as we mentioned, and I'm sorry to say that we don't have the same definition of terrorism around the table," the French president insisted.

"When I look at Turkey, they now are fighting against those who fight with us, who fought with us, shoulder to shoulder, against Isis. And sometimes they work with Isis proxies," he said.

Trump had also lashed out at Macron for Europe refusing to take back the foreign fighters imprisoned in north-east Syria.

He defended Turkey's decision to buy the Russian defence system - but then did not rule out imposing sanctions against Ankara for the purchase.

Trump also credited himself for shoring up an additional $130bn in Nato spending among allies.

Nine Nato members have so far reached the agreed target to spend two percent of their GDP on defence before 2024.