A suicide attack on Wednesday at a funeral in a confessionally-mixed town north of Baghdad killed at least 15 people and wounded 18 others, security and medical officials said.

The attack took place in the town of Buhruz in restive Diyala province according to a police officer and a doctor from the main hospital in the nearby provincial capital Baquba.

The funeral was for a member of the Sahwa, a collection of Sunni tribal militias who sided with the US military from late-2006 against their co-religionists in Al-Qaeda, helping turn the tide of Iraq's violent insurgency.

As a result, the Sahwa, or Awakening, are often targeted for attacks by Sunni militants who regard them as traitors.

Buhruz is a majority-Sunni town but one with a substantial Shiite minority, and lies in confessionally-mixed Diyala in central Iraq, which remains one of the country's most dangerous provinces.