Iraqi officials say a suicide bombing in the capital has killed at least seven civilians and wounded 23.

A police officer says the suicide bomber set off his payload among a group of day laborers in Baghdad's Tayaran Square on Tuesday. A medical official confirms the toll. Both spoke on condition of anonymity as they were not authorized to brief reporters.

The Islamic State group claimed the attack in an online statement circulated by supporters, saying it targeted Shiite militiamen. In recent months the Sunni extremists have carried out a series of large attacks mainly targeting Iraq's Shiite majority and Shiite-dominated security services.

The attacks come as IS has lost ground on a number of fronts in Syria and Iraq, where it governs a self-styled Islamic caliphate.