The bus carrying high school students was hit by a roadside blast that also injured six people near the city of Mosul today.
At least three children were killed today when a roadside bomb exploded near their school bus in Iraq, police said.
Another six people were injured when the device went off in the Shura area south of the city of Mosul.
Police said the bus was carrying high school students but no further details were available in the immediate aftermath.
It has been more than a year since Mosul was retaken from Islamic State. But children and adolescents are still struggling to cope with their fears that nowhere is safe, a report by Save the Children said in July.
Half of the schools in the conflict-affected areas in and around Mosul have been destroyed. In western Mosul, 62 schools are completely destroyed and 207 damaged, according to the Norwegian Refugee Council.
The city has suffered several bomb blasts in recent months, one of which killed six people in October.
Iraq's security officials have accused Islamic State "sleeper cells" of carrying out insurgent-style attacks in and around the city of Mosul. The group's fighters have waged a campaign of kidnappings, killings and bomb attacks targeting civilians and security forces.