While million of Shi'ites marked a holy day in Iraq, a series of attacks has left at least 57 people dead.
A spate of attacks targeting Shi'ite pilgrims has left at least 57 people dead and 135 injured in central and southern Iraq, said security officials.
Millions of Shi'ites on Thursday were marking Ashura, a day of mourning for the martyrdom of Imam Hussein, the grandson of the prophet Mohammed, at the battle of Karbala in Iraq in 680 AD.
The deadliest attacks were in the central city of Baquba, where suicide bombers blew themselves up at two separate processions of Shi'ites and killed a total of 48 and injured 107.
In one attack, the bomber, wearing a military uniform with an explosive belt around his waist, blew himself up amid a crowd of mourners in the district of al-Sadiya, Ahmed Salah of the Baquba Police Command told dpa.
Local authorities declared three days of mourning for the deaths, reported independent broadcaster Alsumariya TV.
In the southern city of Kut, three back-to-back bombs went off as a Shi'ite procession was under way, killing nine people and wounding 28.
Iraqi authorities have deployed tens of thousands of security forces to protect millions of pilgrims heading to the holy southern city of Karbala.
Video on local TV stations showed marching Shi'ites carrying traditional black banners, emblematic of their mourning.
Shi'ite pilgrimages and commemorations are frequent targets for attacks by Sunni militants in Iraq, where sectarian violence has peaked in recent months.
According to UN estimates, 979 people were killed in attacks in the country in October.