The deadly attack occurred at 14:00 local time (1100 GMT), whena suicide bomber entered a lunch gathering held by Sheikh Mohammed Abdullah Salih, a Sunni tribal leader in al-Yusufiyah, some 30 km south of Baghdad, anonymous local police source told Xinhua.
The suicide bomber wearing an explosive belt detonated the vest when Sunni and Shiite tribal leaders were gathering during national reconciliation meeting at Salih's home.
Most of the victims were tribal leaders, and some of them were security service personals.
Violent tribal rivalries persist in Iraq despite a sharp overall decline in bloodshed over the past year.