The group was running 'terrorist schools' to keep the children, some as young as seven, chained on to beds while they were taught an extreme version of Islam.
The kids, all under 10-years-old, were taught about suicide bombings and told they would go to paradise if they killed themselves in 'martyrdom-operations,' the Daily Mail reports.
According to the paper, terror investigator Neil Doyle revealed the pictures of the locked-up children after authorities carried out a raid on a school in Mogadishu
The raid was one of a number of operations sanctioned by the government in recent months and led to the arrest of 200 people.
The paper quoted a teacher, as saying that the children were in chains because they missed classes.
The latest revelation comes just days after Al Shabaab claimed responsibility for a remote-controlled bomb that killed at least eight Somali government troops when it hit their vehicle in Mogadishu.