The attack took place in Jalawla, 130km to the north-east of Baghdad.
Jalawla is home to a mixed population of Shia Kurds and Sunni Arabs.
Mohammed Osman, a local official in Khanaqin to the north of Jalawla, said the bombing happened as a local family was receiving condolences.
Earlier, nine people were killed and 23 injured when a bomb exploded near a car repair workshop on the outskirts of Baghdad.
The blast occurred in the Abu Ghraib area in the west of the capital.
Some sources said it exploded at a bus terminal.
