Bomb attacks and shootings have killed at least 75 people in Iraq, police and hospital sources said, making it one of the bloodiest days in months.
In the deadliest incident, a bomb blew up in a funeral tent where mourners were marking the death of a Sunni Muslim pro-government militiaman, police said.
It killed 18 people and wounded 16 in Shatub, a village south of Baquba.
Assailants detonated roadside bombs near a bridge in Ain al-Jahash in the north west of the country, 60km south of Mosul as an army patrol was crossing it.
Six soldiers were killed and eight people were wounded, six of them civilians, police said.
Gunmen killed seven truck drivers, kidnapped two and set three trucks ablaze in the mainly Shia district of Maamil in Baghdad's eastern outskirts, police said.
At least eight bombs struck the capital, mostly in Shia districts, killing 40 people and wounding a further 88, police and medics have said.
A car bomb in Dujail, a Shia town 50km north of Baghdad, killed three people and wounded seven.
Two years after US troops left Iraq, violence has climbed back to its highest levels since the Sunni-Shia bloodshed of 2006-2007, when tens of thousands of people were killed.
The army is locked in a stand off with Sunni militants who overran Falluja, a city west of Baghdad, more than two weeks ago in a challenge to Prime Minister Nuri al-Maliki's Shia-led government.
They are led by the al Qaeda-linked Islamic State of Iraq and the Levant (ISIL), which is fighting in western Iraq and Syria to carve out a cross-border Islamist fiefdom.
"The battle will be long and will continue," Mr Maliki said on state television, calling for world support. "If we keep silent it means the creation of evil state lets that would wreak havoc with security in the region and the world."
Mr Maliki has ruled out an assault on Falluja by the troops and tanks ringing the city of 300,000, but has told local tribesmen to expel ISIL, which has exploited anger among minority Sunnis against a government they accuse of oppressing them.