Iraqi authorities say a pair of bomb attacks has killed four pro-government militiamen in the center of the country.

Police and medics say the first bomb went off Sunday morning, hitting a passing patrol of Sahwa fighters near the town of Mishahda and killing two of them. They say the second bomb exploded minutes later as another vehicle of Sahwa militiamen rushed to the scene. Two fighters were killed in that blast.

The Sahwa, or Awakening Councils, are predominantly Sunni militias who began allying with Iraqi and U.S. forces in the fight against al-Qaida militants in late 2006. Sahwa fighters have been frequent targets of insurgents who accuse them of being traitors for supporting Iraq's majority Shi'ite-led governments.