Iraqi officials have increased security in the holy city of Karbala where tens of thousands of pilgrims are gathering for Ashura, one of the most important holy days for Shi'ites.
Authorities have deployed at least 23,000 security force members around the city, located south of Baghdad.
Police say a roadside bomb targeting Shi'ite pilgrims exploded in Baghdad Tuesday, killing at least 39 people. Iraqi officials say at least four Shi'ite pilgrims were killed in a suicide bombing near the capital, Monday.
Ashura is celebrated by Shi'ite Muslims around the world. It commemorates the death of Imam Hussein more than 1,300 years ago. He was a grandson of the Prophet Mohammed.
Some information for this report was provided by AFP.