Another 40 people were wounded in the 8:30 am (local time) attack, the officials said.
The bomber struck in al-Balassim, part of Radwaniyah, a Sunni Arab former insurgent hotspot, 25 km from the Iraqi capital, an interior ministry official said.
Most of the victims were Sahwa (Awakening) fighters, members of a Sunni Arab militia, also known as the ‘Sons of Iraq’, that with the US backing took up arms against the al-Qaeda in late 2006.
The force, recruited from among tribesmen and former insurgents, is credited with turning the tide in the war against al-Qaeda in Iraq.
Control of the Sahwa passed to Iraq in October 2008, and their wages — said to have been cut from $300 under US leadership to $100— have been paid, often late, by the Shiite-led government.
Baghdad has promised to incorporate 20 per cent of the Sahwa into the police and military and find civil service jobs for many of the rest, but the process has been slow and is fraught with risks.
In the past six months many Sahwa fighters and members of their families have been killed in revenge attacks.
The former rebels and tribesmen fret that they are not only in the firing line for the al-Qaeda but also viewed with suspicion by the Shiite-led central government.
US and Iraqi officials have warned of the dangers of an upsurge of violence if negotiations on forming a new governing coalition continue to drag on, giving insurgent groups an opportunity to further destabilise the country.
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