Some 45 people were reported killed and more than 200 others injured in a series of bombings across Iraq.
In the southern city of Karbala, 13 people, including a number of Iranian pilgrims, were killed in two car-bomb explosions in a crowded restaurant and shopping area.
Karbala is a destination for thousands of Shi'ite pilgrims who visit the golden shrines of two revered imams each day.
Police said 13 people, most of them policemen, were also killed and nearly 60 others injured in the northern city of Kirkuk.
Casualties were also reported in Baghdad, Samarra, Hillah, Baiji, Daquq, Dhuluiyah, and elsewhere.
Reports say the series of attacks appeared to target security forces and Shi'ite areas.
There was no immediate claim of responsibility for the apparently coordinated multiple attacks, but the Sunni terror group Al-Qaeda has in the past claimed similar bombing strikes.
The last widespread wave of attacks across Iraq on February 23 killed 55 people and injured at least 225.
Arab League Summit
The violence came as Iraqi authorities are preparing to host an Arab League summit in Baghdad next week for the first time in 20 years.
The authorities said they would deploy an unprecedented number of security forces to protect the capital for the summit.
Reports said an estimated 26,000 police and soldiers were expected to be stationed in Baghdad.
To encourage people to stay at home, officials announced a weeklong federal holiday in Baghdad from March 25-31.
A curfew will be imposed in parts of Baghdad on March 29, when the Arab heads of state arrive in the city.
Roads near the Green Zone, where the summit will be held, will be shut off. Two attacks on March 20 occurred outside of the heavily protected area.
Plans to host the summit in Baghdad last year were postponed in part because of security concerns.
With AP, Reuters, and AFP reporting