At least three schoolchildren were killed and six people wounded when a roadside bomb exploded near the northern Iraqi city of Mosul on Thursday, police and medical sources said.
Police said the bomb went off near a bus carrying the high school students in the Shura area to the south of Mosul. No further details were immediately available.
The city, which was recaptured from ISIS militants last year, has suffered several bomb blasts in recent months, one of which killed six people in October.
Iraq's security officials have accused ISIS "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.