Iraqi authorities say a car bomb in central Baghdad has killed at least 70 people, in an attack that targeted mainly poor Shi'ite day laborers waiting for jobs.
Officials say the bombing on Tuesday also wounded more than 230 people in Baghdad's Tayaran Square.
A suicide bomber in a pick-up truck set off his explosives after attracting a large crowd by pretending to offer work.
Iraqi Prime Minister Nouri al-Maliki blamed the attack on sympathizers of former dictator Saddam Hussein and Sunni extremists.
Meanwhile, the U.S. military in Iraq says a bomb caused "minimal damage" to the entranceway of the Golden Mosque in Samarra -- a revered Shi'ite shrine. The military says the explosion occurred as demolition teams sought to remove the bomb.
The U.S. military also announced three Marines died on Monday from combat wounds sustained in restive Anbar province west of Baghdad.
In February, an explosion destroyed the dome of the Golden Mosque, sparking a cycle of sectarian violence.
In other news, hundreds of people marched today in the northern city of Kirkuk to protest a U.S. report that calls for delaying a referendum on Kirkuk's future status.
The U.S. bipartisan Iraq Study Group report warns that a referendum could trigger an explosion of sectarian violence in Kirkuk.
Iraq's constitution calls for the fate of the oil-rich city to be decided in a regional referendum by the end of next year. Kurdish residents want the city to merge with Iraq's autonomous Kurdish region, but Arab and Turkomen residents reject that idea.