Dozens were injured when the bombs exploded at the Nakheel Mall opposite the oil ministry in eastern Baghdad at around midnight local time (2100GMT), the source said on condition of anonymity due to safety fears.
The suicide attack was claimed by Daesh in an online statement published by the Amaq News Agency linked to the terror group.
The mall in Palestine Street was open late in the run-up to next week’s Eid al-Adha feast.
Daesh has suffered defeats across Iraq and Syria in recent months, leading some observers to predict a rise in bombings on soft civilian targets as its military strength is eroded.
Anadolu Agency