Bombers have struck Shi'ite worshippers in two Iraqi cities as part of a series of attacks that killed more than 50 people Tuesday.
At least three dozen Shi'ites were killed in attacks in the town of Mandali, close to the Iranian border and in nearby Khanaqin, while performing rituals for the Shi'ite holy day of Ashura.
Scores of others were wounded.
In Baghdad, at least five Shi'ite pilgrims were killed when their car was ambushed. Also in the capital, mortar shells slammed into a Sunni neighborhood, killing at least 10 people.
Thousands of Iraqi soldiers and police are deployed around the city of Karbala, where nearly two million Shi'ite pilgrims have gathered for Ashura.
Ashura marks the seventh century killing of the Shi'ite Imam Hussein, the grandson of the Prophet Muhammad. Shi'ites believe Hussein was the prophet's heir. Hussein's death solidified Islam's split into rival Sunni and Shi'ite branches.
Separately, the U.S. military says one U.S. Marine died Monday during combat operations in western al-Anbar province, while a soldier was killed in an accident near the city of Nasiriyah, south of Baghdad.