At least six people were killed in a car bombing in Baghdad on Saturday targeting Shiite pilgrims heading to the holy city of Karbala for a religious festival, police and hospital officials said.
The attack was the latest in a wave of bombings since Thursday that have now killed at least 36 people, most of them pilgrims, despite a massive security operation.
Saturday's attack, in the northeastern Baghdad district of Ur, also wounded 11 people, the officials said.
The worst attack against the pilgrims occurred on Thursday when two women suicide bombers detonated their explosives-packed vests in Iskandariyah, south of Baghdad.
The blasts killed 22 people and wounded at least 73, most of them young men but also women and children.
More than 40,000 soldiers and police have been mobilised, including 2,000 female security workers, to boost security in and around Karbala ahead of a festival on Sunday commemorating an eighth century imam.
Tens of thousands of Shiites are heading on foot to Karbala to venerate Imam Mahdi, who vanished as a boy and whom Shiites believe will return to bring justice to the world.
Bloodshed routinely marks Shiite pilgrimages. On July 28, three female suicide bombers blew themselves up in a crowd of pilgrims near a Baghdad shrine, killing 25.