Children the "Islamic State of Iraq and Syria" (ISIS) refers to as "cubs of the caliphate" have vanished from the Syrian city of al-Raqa as liberating forces close in on the group's stronghold, residents tell Diyaruna.

Meanwhile, the group has set up other "cubs' schools" in rural Damascus, where it has been training children to become fighters.

This move has been widely construed as an attempt to maintain the human reservoir that will allow ISIS to continue to carry out terrorist operations in the future, even if its actual presence on the ground is eliminated.

"ISIS's child soldiers, who used to be seen from time to time roaming the streets with their weapons, can no longer be seen in al-Raqa," said local resident Amjad al-Mohammed, using a pseudonym out of fear for his safety.

The children, who are of various nationalities, have been housed in camps on the outskirts of the city, he told Diyaruna.

Some are orphans, assembled by ISIS elements from several parts of Syria, he said, while others were handed over to ISIS by their parents in exchange for financial compensation to become the "fighters of the future".

Al-Mohammed said he has been able to confirm that many of the children have been sent to the battlefronts in rural al-Raqa to fight against the Syrian Democratic Forces (SDF).

This move is designed "to make up for the shortfall in numbers the group is suffering from", he said, noting that many of the children had only been enrolled in the "cubs of the caliphate" camps for a few weeks.

It is clear the group is using these children, and other youth it has detained on various pretexts, to make up for a shortfall in the number of its fighters, he said.

"Youth are being arrested on various charges and transported directly to dangerous areas to carry out logistical tasks such as digging trenches, transporting gear and equipment or delivering food to fighters on the fronts," he added.

Preying on parents, children

As the battle for al-Raqa gathers force, and ISIS training camps in the area are forced to close, the group has opened a school to train child fighters in Hajar al-Aswad, south of Damascus, said activist Tariq Abdo.

According to Abdo, who is co-founder of the "No more recruitment or use of children in armed action in Syria" initiative, the group has been working hard to promote the new school through home visits.

Based on its promotional material and information provided by some of the parents ISIS attempted to persuade into sending their children, the school admits 12-year-olds and those who have completed their elementary education.

Students are to stay at this school for about two years and graduate as fighters, after attending classes on sharia, military sciences and other subjects.

In its promotional campaign, Abdo said, the group claims the objective of the school is to prepare a "new generation of fighters to defend Muslims".

Recruiting children and filling their heads with deviant ideology "is a very serious matter that must be addressed and curbed", said terror group expert Gen. Abdul Karim Ahmed, who is retired from the Egyptian military.

"These boys will be turned into mobile bombs that could explode at any moment when they receive the order, even if the group’s actual presence in Syria is eliminated," he told Diyaruna.

Obtaining a complete list of the names of these children and their nationalities or place of birth is necessary to find them and rehabilitate them, he said, noting that there is no telling what catastrophes they might cause otherwise.