A suicide bomber has killed 10 people in an attack in the city of Baquba, north of the Iraqi capital Baghdad.
Most of the casualties are said to be members of a local volunteer force opposed to al-Qaeda. Another 15 people were wounded in the explosion.
This is the latest in a number of attacks on members of the mainly Sunni Muslim volunteer forces, known as Awakening Councils.
On Tuesday, a suicide bomber killed 30 people attending a funeral in Baghdad.
The funerals for those killed on Tuesday took place on Wednesday.
Also on Tuesday, a number of Iraqi ministries released data suggesting that the number of civilians killed in Iraq was continuing to fall.
The December death toll was 480, down from almost 900 two months previously and about 2,000 in December 2006.
American military deaths also fell in December, dropping to 21 compared to more than 100 in December 2006.
US commanders attribute the reduced violence to their "surge" strategy, which involved sending thousands more American troops to Iraq in 2007.
Other likely factors behind the fall in deaths are the emergence of Sunni tribal groups opposed to al-Qaeda and the truce called by Shia militia leader Moqtada Sadr.
However, US military officials have warned that security improvements might not last unless Iraqi political leaders make progress with reconciliation.