Reports from Iraq say about 50 people were killed and dozens wounded when at least 10 bomb blasts rocked the capital, Baghdad, and other parts of the country.
Iraqi government helicopters hovered low in the skies of Baghdad while a thick trail of black smoke etched the horizon after the blasts.
One of the deadliest attacks hit a bus terminal with service to the town of Baquba. Witnesses said several explosions sent people running for cover and spread shrapnel in all directions.
Passengers were fleeing the station in panic in different directions, said a shopkeeper in the area. He said terrorists deliberately targeted places where people congregate. Only innocent people are hurt by such attacks, he added.
Other bombings hit crowded markets in mainly Shi'ite areas of the Iraqi capital. Another blast tore through a parking area in front of a government court.
According to a woman who works at the court, a car bomb blew up outside while a judge was hearing cases, destroying a number of vehicles, including her own.
Iraqi state television reported lower casualty figures for the attacks than most other Arab and Iraqi TV channels. Sky News Arabia said Interior Ministry spokesman Sa'ad Ma'an put the death toll in Baghdad at 32 people with dozens injured.
In the northern city of Mosul, a car bombing targeting soldiers killed at least 12 people, including civilians.
Khattar Abou Diab, who teaches political science at the University of Paris, said the conflict in neighboring Syria is spreading violence to Iraq as the Sunni and Shi'ite protagonists in both countries intensify their bitter historic struggle.
He said the Sunni-Shi'ite conflict, which began in the Iraqi town of Karbala, has come back to hit Iraq as the war in neighboring Syria metastasizes. He said borders are losing their importance as Sunni militants strike targets in both countries and Shi'ite militiamen from Iraq help the Assad regime in Syria.
Abou Diab also said that regional powers are trying to settle scores in both Iraq and Syria by using local proxies. He said the weak central government in Iraq and the increasing Iranian influence over it have made the situation worse, as security forces prove incapable of controlling the violence.