More than 30 people were killed in an attack on a market in al-Mahmudiyah about 20 kilometres south of Baghdad, a source in Iraq's Defence Ministry said.
The source said on Saturday that the detonations came from three explosives-laden vehicles. At least 50 people were wounded in the blasts.
Initial reports in Pan-Arab channels said that unknown perpetrators also fired mortar shells at the city market.
Earlier in the day, another suicide bomber had detonated his explosives belt on a commuter bus west of Baghdad, killing four civilians, according to police sources.