At least 13 Iraqi volunteer fighters, including a leader, were killed and eight others wounded in a suicide attack in Baquba city Thursday, an Iraqi medical source said.
It was initially reported that four volunteer fighters had been killed and eight were wounded in the suicide bombing.
The bomber blew himself up targeting a volunteer centre linked to local public committees in Baquba, according to the source.
Public committees are formed by local tribespeople who volunteer to help police and the army enforce security and eliminate militants from the al-Qaeda terrorist network and other militias.
This model of volunteer resistance, primarily supported by the United States, was first introduced in Anbar province and its surroundings.
It was well received and spread into Diyala province and Baghdad, especially in the predominately Sunni and ethnically-mixed areas.
The Iraqi government recently decided to integrate the tribal fighters into the security forces to help combat the ongoing insurgency.
Baquba, the capital of Diyala province, some 60 kilometres south- east of Baghdad, is a flashpoint of insurgency by Iraqi militant groups backed by al-Qaeda operating in Diyala.
A large-scale security offensive mounted by US and Iraqi troops drove insurgents into the nearby villages and surrounding countryside in June.
TAGS: Middle-East IraqSuicide attackerterrorism