Washington- The boy appears to be under 12 years old; he hugs his father, climbs into an armored vehicle packed with explosives, and kisses his father’s hand before departing on a mission that will end his life.

According to new research that indicates the terrorist group is sending youths to their deaths in greater numbers, the attack in Aleppo last month was one of at least 89 suicide missions over the past year in which ISIS employed children or teenagers.

The father-son sequence was memorialized in propaganda photos released last month by ISIS, adding to an expanding collection of online tributes that provides insight into how the organization uses children in both combat operations and mass-casualty attacks on civilians in Iraq and Syria.

Washington Post has acquired a report that will be published on Friday by the Combating Terrorism Center at the U.S. Military Academy at West Point, stating that “ISIS is mobilizing children and youth at an increasing and unprecedented pace.”

The report includes a study that describes ISIS’s use of children in suicide attacks as part of a broader strategy to cultivate a generation of school-age militants indoctrinated in the group’s ideology and completely inured to its extreme brand of violence.

Since its emergence as a dominant force in Syria, ISIS has frequently cast children in roles designed to shock outsiders.

A video released last month showed a child in an ISIS headband pressing the button of a remote control, thus exploding a bomb strapped to a car containing three accused spies.

However, the new study is the first comprehensive catalog of cases in which ISIS used children in missions where they were expected to die. Roughly 60 percent of the victims were categorized as “adolescents,” meaning aging between 12 to 16 years old; none was older than 18, and some were as young as 8 or 9 years old, according to researchers at Georgia State University.

At least 11 children or adolescents were killed in ISIS operations in January, compared with six in the same month a year ago, according to the report, titled “Depictions of Children and Youth in ISIS’s ‘Martyrdom’ Propaganda.”

The use of children in combats has often been a sign of desperation, as was the case in Nazi Germany in the closing months of World War II. Nonetheless, researchers said that ISIS is not being forced to rely on underage fighters because of dwindling adult ranks.

Instead, they said that the group seems to employ children for reasons including their propaganda impact and ability to evade detection, as well as a system of values that regards even young lives as subordinate to the cause of reestablishing a “caliphate.”

“It is striking that children are being integrated into the ISIS war machine not as substitutes but as soldiers and suicide attackers fighting alongside adult militants,” said Charlie Winter, a senior research associate at Georgia State and co-author of the report. Winter said that the practice could intensify if ISIS loses territory and fighters.

“We know that there are a lot more children being recruited than eulogized,” Mr Winter said. “As the military situation becomes more difficult for ISIS in the months and years to come, we’ll see more instances of youths being used on the battlefield.”

The vast majority of the children and teenagers used in suicide missions were from Iraq or Syria, where ISIS controls an area the size of West Virginia, according to the report. Yet, others came from the Middle East and North Africa and at least four were from Western nations, with two from Britain and one each from France and Australia.