A lot has changed for 32-year-old Amar Al Alil since the Syrian revolution began six years ago.

In 2011, work was scarce and he jobbed in construction when the opportunity arose. The country had not yet unravelled. He hadn’t seen public beheadings by Isis, or his teenage neighbour whipped for playing football.

The whirr of US Apache helicopters dropping bombs wasn’t a familiar sound, and he had not been forced to flee his home town of Raqqa, fearing for his life.

Now, as a new member of the SDF (Syrian Democratic Forces), he can reach into his belt and change a Kalashnikov ammunition cartridge with his eyes closed, miming the process while sitting in a tent next to his wife and three-week-old daughter in an internally displaced persons (IDP) camp in Ain Issa, 45 miles (72 kilometres) north of the city.

“I joined the SDF because I felt like I had to. Isis stole three years of our lives. I’m fighting for freedom for the others, and for revenge,” he said.  

After dodging Isis sniper fire, mines and US-led coalition bombing to escape the capital of the militants’ so-called caliphate across Syria and Iraq, Amar and his six months pregnant wife Delal made it to Ain Issa  - along with at least 300,000 other civilians who have fled in total since the US-backed Arab-Kurdish SDF offensive to recapture the city began.

The newly-established IDP camp is well run considering there are no expert international NGOs on the ground in Syria anymore – but like all IDP and refugee settlements, it’s still chaotic, and the 9,000 residents with no home to go back to are trapped in poverty.

For some, picking up a gun is becoming the obvious answer.

“We are encouraging people to join the SDF. When the fighting is done we are the ones who will have to rebuild it, after all,” said Jilal, the camp’s de facto leader.

“I’m old. I can’t fight. ‘But what are you going to do?’ I ask them. ‘Sit around doing nothing here? Or be useful?’”

The SDF, formed in 2015, is a joint Kurdish-Arab ground force created by the self-declared autonomous Kurdish administration, funded and equipped by the US. Their aim is to destroy Isis, and in the process create a “secular, democratic and federal Syria”.

There have been several reports of internal conflict between its many component units, not to mention allegations of extrajudicial killings and unlawful treatment of men believed to be captured militants.

But the SDF has made almost all of the important gains against Isis in Syria over the last year, winning it the continued support of new US President Donald Trump. 

Amar is not a volunteer. The standard SDF salary is $200 a month – considerable in a country where the lira has lost more than half of its value since the war began; the Syrian pound is now worth just 14p.

More and more recruits are signing up, Jilal added – he estimated about 100 since June – and in March, the Pentagon said it believed the SDF’s 40,000 troops to be 60 per cent Arab.

Just before The Independent visited, dozens of civilians fleeing Deir Ezzor in Syria’s east had also arrived at Ain Issa. The Isis-besiged town is currently being wrestled back by the Syrian government, helped by Russian air power.

The UN, whose Human Rights Council met to discuss the plight of Syrian civilians in New York on Monday, has called for restraint from all sides fighting in Deir Ezzor after a dramatic increase in civilian deaths in the region in recent days.

Isis, desperate after heavy losses across Syria and Iraq, announced in August that men of fighting age across the governorate were expected to report for military service.

Around twenty young Arab men – having just made it to Ain Issa – had immediately requested to join the SDF, getting on buses for a nearby training academy.

For some families, the SDF’s seemingly growing popularity with Arab recruits means yet more anguish.

Abu and Adnan of the Saleh family, who have been in Ain Issa since April, decided to join the battle for Raqqa three months ago. Adnan, the elder, is still at the front line. Seventeen-year-old Abu, however, was killed by a sniper in July.

“Yes, his loss is painful, especially after we were all reunited when some of us managed to leave the city,” his big sister Shemsa said, stroking a Kurdish-style martyr picture of Abu.

“But he died helping others. We are very proud of that. And his memory will be cherished.”

Amar also said he’d be happy to die fighting for the SDF because he believes in their cause. Even though he never imagined picking up a gun before the war, now he can’t imagine not being able to fight.  

“She can too, if she wants,” Amar said, gesturing towards his tiny new daughter Aaia, who was sleeping fitfully on a pillow. “Whether we are still at war or not. She will know how to defend herself.”