The coordinated attacks followed shootings and bombings in the north earlier in the day that killed six others.
Today's explosions struck shortly before the evening iftar meal that ends the daylong fast during Ramadan.
At least eight people were killed and 15 were wounded in the southern port city of Basra when a car bomb and then a follow-up blast went off near an office of a Shiite political party, according to two police officers. Basra is a major oil industry hub 550 kilometers southeast of Baghdad.
Police reported additional car bomb explosions that left four dead in a commercial street in the Shiite holy city of Karbala, five near an outdoor market in Nasiriyah and six near a Shiite mosque in Musayyib, and more than 60 wounded in total.
Earlier in the day, police said gunmen killed two soldiers in an assault on their security checkpoint in the restive city of Mosul, 360 kilometers northwest of Baghdad.