"Daoud" said he wanted to fight "for revenge" after the Islamic State of Iraq and the Levant (ISIL) swept into Iraq's Sinjar district in August 2014, killing thousands of adherents of the Yazidi religious minority and taking thousands more captive.

Daoud's family managed to flee, taking an escape route opened up by the People's Defence Forces, the armed wing of the Kurdistan Workers' Party (PKK). Those forces offered training and weapons to a Yazidi militia, the Sinjar Resistance Units. Six months later, Daoud, whose real name isn't used for his safety, joined the militia. He was 15.

Human Rights Watch (HRW) documented 29 casesin which armed groups linked to the PKK, had recruited children in Sinjar and in the Kurdistan Region of Iraq - even though the group's commanders had pledged to end the practice.

WATCH: Child soldiers 'recruited in Syria war' (1:38)

'War crime'

The Yazidis and the Kurds have suffered appalling persecution. But in their efforts to protect their people, commanders are committing their own abuses by using children as soldiers. This can cost those children a future, and sometimes their lives.

None of the 29 children whose cases we documented was forcibly recruited, but it is prohibited under human rights law for armed groups to use children, even if they "volunteer". And if the children are under 15, it is a war crime.

The children weren't allowed regular contact with their families. A Kurdish family in Halabja, the town Saddam Hussein attacked with chemical weapons in 1988, said that PKK officials had rebuffed their attempts to contact their 16-year-old son since he left to join the group more than a year before.

As for Daoud, he was shot during fighting in Sinjar. He called home just twice over nine months from Syria where he was receiving medical treatment. He never told his family what happened, he said.

Another Yazidi boy saw a 16-year-old friend killed in battle. Neither had received any psychological support after they had returned to the displaced people's camps where their families are.

Recruiting children as fighters is exacerbating their hardships, not ameliorating them.

 

Once they joined up, some children were not allowed to leave. In the worst the HRW found, witnesses described the recapture and brutal beating by fighters of a 13-year-old Yazidi girl who had argued with her commander and tried to escape.

In February, residents of Sardashti, a town in Sinjar, told the HRW they found her limping along a road with a broken leg, pleading for help. They tried to help her, but her former sisters-in-arms tracked her down and took her away.

Some child soldiers said they received an informal education from their commanders, but many, like Daoud, dropped out of school and never went back. After missing out on an education, a child's reward for military service is often life-long poverty.

Daoud, who is now back in a camp for displaced people, is looking for unskilled work. A boy in another camp said he joined the Yazidi militia when he was 14 "to kill some ISIL" and fought for nearly two years, but that now, "I have no job. I have no idea what I'll do."

Escaping desperate circumstances

WATCH: Iraqis return to towns captured from ISIL (2:38)

Vengeance aside, children may try to join armed groups to escape desperate circumstances. In the camps, families live in prolonged, aid-dependent temporariness.

In Sinjar, where the economy remains in shambles, it is as bad or worse. Only eight of the 225 former Iraqi public schools in the district were functioning as of September, a school director said.

In one town, Khanasoor, the Sinjar Resistance Units have turned one former school into a barracks. The PKK had sent volunteer teachers to another empty school, but none had a high school education. Last year, the party's militia recruited some of the pupils.

Recruiting children as fighters is exacerbating their hardships, not ameliorating them. In interviews Yazidis in Sinjar repeatedly and spontaneously compared the Kurdish group with ISIL on the issue of child recruitment and indicated that the People's Defence Forces is wearing out its welcome.

READ MORE: Iraq's child soldiers - 'What happened to our boys?'

A father in Sinjar said his son had left 18 months earlier with a group of 16-year-old boys to join up. The father had asked party officials to bring the boy back, but was rebuffed, and doesn't know if his son is alive or dead.

"He is still a baby," the father said. "He said he wanted to be a doctor, he was very good at school." He said the use of child soldiers risked "starting a war between the Yazidis" and the armed group.

Among the families the HRW spoke to, child recruitment is losing hearts and minds, and it is costing boys and girls dearly. The PKK leadership should clearly denounce it, and affiliated armed groups should demobilise all children in their ranks.

Zama Coursen-Neff is the children's rights director at Human Rights Watch.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.