The 5:00 pm (1400 GMT) attack wounded 47 other people in Musayyib, a mostly Shiite town 60 kilometres (35 miles) south of Baghdad, a police officer and a doctor at Musayyib hospital said.

The attack was the second to target Musayyib in recent days -- seven people, including three women and two children, were killed when three houses were blown up on December 31. The victims were apparently targeted because they were Shiites, officials said.

The attack came as pilgrims were returning from the shrine city of Karbala after the conclusion of Arbaeen mourning rituals, which have been a repeated target for militants.