Police officials said the explosion took place in the morning in Tahrawa, a village inhabited by families from the Shabak ethnic group. The village is near the city of Mosul, 360 kilometres (225 miles) northwest of Baghdad. Police said 43 people were wounded in the attack.
The Shabak have their own distinct language and belief system, which is an offshoot of Shiite Islam. Most live in villages east of Mosul, the provincial capital of the ethnically mixed Ninevah province, which is predominantly Sunni Muslim.
Hospital officials confirmed the toll from the attack. All officials spoke on condition of anonymity because they were not authorised to release details to journalists.
According to UN figures, 8,868 people were killed in Iraq in 2013. The UN mission said that May was the deadliest month so far this year, with 799 Iraqis killed in violence, including 603 civilians.
Iraq is currently grappling with the worst surge in unrest since 2006 and 2007, when a wave of sectarian attacks pushed the country to the brink of civil war.