Rmeilan, Syria - A year and a half ago, the rich oil fields of Rmeilan in the Hasakah province of northeastern Syria were the scene of intense battles between Kurdish forces, known as the People's Protection Units (YPG), and the al-Qaeda offshoot Jabhat al-Nusra.

Evidence of the deadly battles across the arid land remain: Long, deep trenches, piles of sandbags and sniper positions stretch into the distance, where snow-capped mountains rise. But today, rather than Jabhat al-Nusra, the threat comes from the Islamic State of Iraq and the Levant (ISIL).

In Rmeilan, amid the thick smoky air from nearby oil refineries, a heavily fortified Kurdish military base is filled with more than 20 teenage members of the YPJ, the female branch of the YPG.

Wearing military uniforms and holding Kalashnikov rifles, the girls - all under 18 - say they are ready to take on ISIL.

"As soon as I joined the YPJ, I found my truth and that is, the truth about our history and of Kurdistan," Dilocan, a slight 14-year-old with long brown hair, told Al Jazeera. "I came here because armed terrorists are trying to take over our land. Our land is our honour. Many martyrs [have] died trying to protect it."

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In late 2013, the YPG issued a military order prohibiting the recruitment of people under the age of 18. International law prohibits the use of children as participants in direct hostilities, including at checkpoints, spying and in combat.

After a scathing Human Rights Watch report in June that criticised the Kurds' use of child soldiers, the YPG and the region's self-declared autonomous government signed the "Deed of Commitment", a document produced by the Switzerland-based organisation Geneva Call, aimed at protecting children in armed conflict.

As a result, the YPG was forced to demobilise 149 child soldiers from its ranks. The YPG also created a new "non-combat" category for children between 16 and 18, allowing them to be involved in the group's political and educational activities.

We had a strong reaction when we had to demobilise the children from service. It has been hard to make children understand why; they saw themselves as soldiers, as grown adults. - Galia Naamet, responsible for child soldiers in the Jazirah canton

Despite this commitment, Al Jazeera met countless underage fighters at bases, checkpoints and frontlines across the region. The YPG's official spokesperson, Redur Khalil, said that while efforts had been made to demobilise all children from its ranks, cases still existed.

"It is not completely strange that cases still exist," Khalil told Al Jazeera. "When we find more underage kids, we hand them over to the Defence Committee. Anyone under 18, without using weapons, is still allowed to work but in special camps away from the frontline."

The Defence Committee of the self-declared autonomous government in the region, has set up six training camps for children who were demobilised and for those who want to join Kurdish forces but are underage.

According to Khalil, Kobane - where Kurdish forces, aided by US-led air strikes, have been fighting a fierce battle against ISIL - was a "special case" wherein the YPG had been unable to verify whether underage fighters were involved.

Galia Naamet, who is responsible for child soldiers in the Jazirah canton, one of Syria's three Kurdish enclaves, said the Defence Committee camps were designed for children between 16 and 18, but children as young as 13 had been allowed to join.

"It is important to understand that everyone has been influenced by the YPG, so it has been hard to close the door to a certain group of society and that is, those under 18," Naamet told Al Jazeera. "We had a strong reaction when we had to demobilise the children from service. It has been hard to make children understand why; they saw themselves as soldiers, as grown adults."

She said the camps, which were still in the process of finalising a programme, taught Kurdish sports, political history and women's rights. There was no classic military training, but rather self-defence training, Naamet added.

However, this did not appear to be the case at the girls' camp in Rmeilan.

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Dilocan's day begins at 5:30am with sports such as volleyball or karate, but the rest of the day is spent alternating between military and political training. The girls learn how to use light weapons, including handguns and Kalashnikovs, and they study the teachings of Abdullah Ocalan, the imprisoned Kurdistan Workers' Party leader.

The girls visit their families for three days each month, but for Dilocan, her fellow trainees have become her family.

"I think this was my dream and it will stay with me for life," she said, noting she was frustrated at being unable to go to the frontlines. "Everybody wants to go to war right now. They just won't let us."

Mehmet Balci, programme director for the Middle East at Geneva Call, told Al Jazeera that many Kurdish children were drawn to the YPG for a variety of reasons, including a lack of social and economic opportunities, insecurity and family involvement in the YPG.

"Many Kurdish children are politically motivated and/or indoctrinated from an early age due to the support given by their families to the YPG," he said.

Diljin Nerdin, 15, left school six weeks ago to join the YPG.

"I came here to take on my enemy. I'm sure with my skills that I'm ready to go and fight Daesh [ISIL]," she told Al Jazeera. "No matter how old I am, I'm ready. I'm not scared of going to the frontline."