Police say Saturday's attack was in the mostly Shi'ite town of Musayyib. At least 14 other people were wounded in the blast.
The latest sectarian violence comes one day after suicide bombers killed 79 worshippers at a Shi'ite mosque in the capital.
U.S. officials are calling for all factions in Iraq to exercise restraint after Friday's bombings.
State Department spokesman Sean McCormack said the mosque attack was the work of people trying to divide Iraq and encourage sectarian violence.
Some information for this report was provided by AFP, AP and Reuters .