The attack early Saturday occurred near Fallujah, a former insurgent stronghold about 40 miles (65 kilometers) west of Baghdad.

Suspected Sunni insurgents are blamed for a recent wave of killings targeting security personnel and government workers in Baghdad and elsewhere.

Police officials say the gunmen hauled the brothers from their home in the village of Karmah and shot them execution style. One man worked as a guard for the minister of higher education and the other two for the immigration minister.

The officials spoke on condition of anonymity because they were not authorized to brief reporters.