Muslim Shiite pilgrims left Baghdad on their way to the holy city of Karbala to mark the Shiite mourning day of Arbaeen on Monday. Ahmad Al-Rubaye/AFP/Getty Images via WSJA suicide bomber believed to be a woman killed at least 46 Shite pilgrims, and injured 106, who were making an annual pilgrimage to the holy city of Karbala, marking the occasion of Arbaeen, a Shia religious observation that occurs 40 days after the Day of Ashoura, the commemoration of the martyrdom of Hussein bin Ali, the grandson of Prophet Muhammad.

The suicide bomber was a member of the procession, typically ‘hundreds of thousands of worshippers, beating their heads and chests in ritual mourning’, according to Al Jazeera.

Today’s attack isn’t the first from female suicide bombers in Iraw. During a pilgrimage last February, a female suicide bomber attacked a tent filled with women and children resting during the walk to Karbala, killing 40 people and wounding 60 others.

Previously, a suicide bomber dressed in women’s clothing and hiding among Iranian pilgrims killed more than three dozen people outside a mosque in Baghdad’s Shia neighborhood of Kazimiyah. via Al Jazeera

Iraqi authorities lack enough policewomen to conduct searches at most checkpoints, and security forces have been reluctant to use bomb-sniffing dogs against people because of cultural sensitivities.via Al Jazeera

Sources: Deadly blast hits Iraq pilgrims Al Jazeera and Suicide Bomber Kills 46 Shiite Pilgrims in Baghdad WSJ.