Emmanuel Macron launched a blistering attack on Turkey’s undermining of the global coalition against ISIS on Tuesday, accusing the Nato country of working with factions to promote its own interests in Syria. The French leader was meeting US President Donald Trump in London at a Nato leaders meeting, where the two sparred over the future of the alliance and Turkey’s recent incursion into north-east Syria. "When I look at Turkey, they now are fighting against those who fought with us, shoulder-to-shoulder against ISIS, and sometimes they work with ISIS proxies,” the French president said as he warned Turkey faced choices about its place in the alliance. “This is an issue, and this is a strategic issue. If we just have discussion about what we pay and we don’t have clearly discussions about such a situation, we are not serious,” he said in reference to arguments over how much Nato members should commit to defence spending. "The common enemy today is the terrorist groups. I'm sorry to say, we don't have the same definition of terrorism around the table," he added. Mr Trump had set the tone for a fractious gathering at a meeting with Nato Secretary General Jens Stoltenberg. The US president took the opportunity to seize the agenda at the start of the two-day summit and hit out at Mr Macron. Mr Trump said the French leader's comments had been "insulting" and nasty". In the run-up to the summit, Mr Macron has said Nato has become strategically "brain-dead," particularly over the US withdrawal from northern Syria. The US president went as far as saying he could see France moving away from Nato, which he described as a surprise, because he believes Paris needs more military support than other members. "I do see France breaking off," Mr Trump told reporters. "I'm looking at [Mr Macron] and I'm saying that he needs protection more than anybody and I see him breaking off. So I'm a little surprised at that." In later discussions with Mr Macron, the US President said he expected the dispute to be sorted out. But the two did argue over foreign fighters languishing in north-east Syria when Mr Trump urged France and Europe to take back captured ISIS members. He joked to Mr Macron: “Would you like some nice ISIS fighters? I can give them to you”. "Let’s get serious,” Mr Macron responded, saying the priority was to ensure ISIS was fully eradicated. He said the fate of foreign fighters would be decided on a case by case basis. “Your number one problem are not the foreign fighters. This is the ISIS fighters in the region and you have more and more of these fighters due to the situation today,” Mr Macron said. “Because sometimes you can have some temptation from the US side, I don’t say from president Trump, but could be the press, to say this is a European responsibility,” he added. For the third summit in a row, Mr Trump is expected to renew demands that European allies and Canada step up defence spending. He has also shown that he will not be looking to mollify Mr Macron who insists that strategic questions must be addressed, like improving ties with Russia and how to handle Turkey. The French President said dialogue with Russia was needed. Mr Macron’s officials told Nato meetings that a tough stance against Russia had become a “Western weakness” as highlighted by the position of the Kremlin in Syria. Thomas Gomart, director of the French Institute of International Relations said: “Accept our own failures, we left the field to the Russians,” he said. Divisions over the issue are deep between the member nations. Justin Trudeau, the Canadian premier, said that concessions to Russia's Vladimir Putin were unlikely to be rewarded with meaningful changes from the Kremlin. “Putin responds to strength not to concessions,” he said. However, Mark Rutte, the leader of The Netherlands, took a more careful stance. “We should have that phone call [with Putin] but it should start with pressure.” US President Donald Trump has accused Iran of killing thousands of protesters while speaking at the Nato leaders’ meeting in London. At a joint press conference with the Nato Secretary General Jens Stoltenberg, Mr Trump addressed widespread popular protests in Iran which have been met by a brutal government crackdown. “Iran is killing thousands of people in Iran right now,” Mr Trump said. He added that civilians had been targeted “for the mere fact they are protesting”. Iran has been rocked, in recent weeks, by the largest protests against the government in the 40-year history of the regime in Tehran. Human rights groups have said possibly more than 450 protesters were killed during the initial four days of violence which followed a sudden hike in domestic petrol prices.