BAGHDAD , Iraq ( CNN ) -- A suicide bomber killed at least 40 people and injured 70 -- many of them women -- during a Shia pilgrimage in northwestern Baghdad Sunday , Iraqi officials told CNN . Pilgrims , pictured above , have gathered to celebrate the Shia holy period of Ashura . The dead included at least 16 Iranians who had come to mark the Shia holy period of Ashura , which commemorates a central event in the history of the movement . At least 32 Iranians were among the wounded . The other casualties were Iraqi , an Interior Ministry official said . The bomber was a woman wearing an abaya , a robe-like dress , said Maj. Gen. Qassim Atta , military spokesman for Fardh al-Qanoon , an interagency domestic security body . She seems to have been targeting women , Atta and an interior ministry source said . The Interior Ministry official declined to be identified . The attack appears to be the single deadliest suicide bombing in Iraq since a bomber killed 47 people in Kirkuk in December 11 . It took place in Baghdad 's Kadhimiya neighborhood , not far from the Imam Moussa al-Kadhim holy shrine . Hundreds of thousands of Shiite pilgrims are expected in Baghdad and the southern Iraqi city of Karbala for Ashura , which falls on January 7 this year . Ashura commemorates the martyrdom of Hussein , the grandson of the Prophet Muhammad . He was killed in battle in Karbala in 680 , one of the events that helped create the schism between Sunnis and Shiites , the two main Muslim religious movements . CNN 's Mohammed Tawfeeq in Baghdad contributed to this report .
Suicide bomber kills at least 40 people and injures 70 in Baghdad . Dead included many Iranians who were marking Shia holy period of Ashura . The bomber was a woman wearing an abaya , a robe-like dress , official says .