The French military’s first airstrike against the Islamic State (ISIS/ISIL) in Syria killed 30 jihadists, including 12 child fighters known as “Caliphate cubs,” reveals a U.K.-based monitor group.

An estimated 20 terrorists were wounded by the September 27 strike on an ISIS training camp in the eastern countryside of Deir Ezzor province in Syria, reports the Syrian Observatory for Human Rights, which uses a network of ground sources to monitor the civil war.

The Observatory learned that the bombing resulted in at least 50 casualties, including the death of 30 ISIS fighters.

Among the dead were 12 children, identified by the monitor group as “Caliphate cubs,” as well as Arab fighters from North Africa, Syria, and Iraq.

Since the beginning of 2015, ISIS has been dependent on the “recruitment of Syrian children at its controlled areas,” reports the Observatory.

Many residents are opposed to the recruitment of children, but the jihadist group continues with the practice.

ISIS argues that they are “adults and are responsible for their decisions,” says the Observatory.

On Sunday, French President Francois Hollande announced that six warplanes had destroyed the ISIS training camp.

France’s participation in the U.S.-led air coalition against ISIS had been limited to the Iraqi skies until Sunday.

The air raid struck “an extremely sensitive site for [ISIS],” said French Defence Minister Jean-Yves Le Drian, describing the target as a “strategic hub” for terrorists traveling between Iraq and Syria.

Minister Le Drian said the attack was carried out in self-defense, noting that France possessed evidence that foreign fighters were being trained in the camps to conduct attacks in Europe, specifically on French territory.

In June, a former young ISIS fighter told BBC that he had trained to fight on behalf of the group alongside many “15 and 16 year olds.”

“There were even many as young as 13 or 14. Those are more eager to fight and wage jihad for the sake of God,” he explained.

According to the United Nations, pro-Bashar al-Assad regime troops, ISIS, and other anti-government forces use children in combat and support roles. The UN has also accused ISIS of torturing and killing children.

In March, the UN Office of the High Commissioner for Human Rights (OHCHR) issued a report that found “widespread abuses committed by ISIL that may amount to war crimes, crimes against humanity and genocide.”

“Compiled by investigators sent to the region last year by the High Commissioner, the report highlights violations, including killings, torture, rape and sexual slavery, forced religious conversions and the conscription of children,” noted the UN.