In the deadliest attack, a suicide bomber killed 15 people and wounded 30 when he blew himself up amid dozens of police recruits queueing outside police headquarters in Fallujah.
The attack was part of a bloody campaign by insurgents to deter young men from joining the Iraqi security forces.
Iraqi police also found 36 bullet-riddled bodies of men killed in apparent sectarian killings.
An interior ministry official said 34 bodies were found in Baghdad.
Two more bodies were found in the town of Al-Mussayib, 80km south of Baghdad.
Suspected insurgents also killed eight Iraqis, including four college students, in Baghdad's notoriously violent Al-Dura neighbourhood.
"Insurgents set up a checkpoint on the highway in Al-Dura and stopped a minibus full of college students. They pulled four students out of the bus and shot them dead," the interior ministry official said.
Hundreds of bodies have surfaced across Iraq, mostly in Baghdad, since the outrage the bombing of a Shi'ite shrine in February.
Iraq's Sunni Arab leaders blame the country's Shi'ite-led interior ministry forces.
It’s claimed the ministry operates death squads that carry out extra-judicial killings of Sunni Arabs.
Two civilians were killed in an explosion near a popular market in Baghdad's Al-Shuala neighbourhood that also left 15 people wounded, he said, and two policemen were killed in Baquba, north of Baghdad.
In another incident, a US civilian was killed and two others wounded today when their vehicle hit a roadside bomb near the southern city of Nasiriyah, a British military spokesman said.
"I can confirm that one US civilian was killed and two wounded in the incident," the spokesman said.
The US military and embassy had no immediate reports of the incident.
Authorities in Baghdad said 176 "terrorists" had been arrested and another 20 killed in a series of operations across the country over the past 72 hours. It did not offer details.
Parliament sits
Meanwhile, parliament convened even as Iraq remains without a new government more than four months after elections for the first full-term post-Saddam Hussein assembly.
Prime minister-designate Nuri al-Maliki is aiming to form the cabinet by May 10.
Deputy parliament speaker Sheikh Khalid al-Attiya told reporters after the end of the session that MPs had "discussed the setting up of a committee to look into the issue of amending the constitution".
Iraq's once-dominant Sunni Arabs have demanded sweeping changes, including the scrapping of federalism, in the charter approved in a national referendum on October 15.
The present charter is strongly backed by the majority Shi'ites and the Kurds who see it offering enough autonomy in the northern Kurdistan region and the southern Shi'ite dominated regions.
Sunni Arabs fear the constitution will lead to the break-up of Iraq and also rob the former elite community of the nation's vast oil wealth, which is concentrated in the north and south.
Freed hostages arrive home
In a rare piece of good news in the strife-torn country, two
freed German hostages reached Berlin.
Rene Braeunlich, 32, and Thomas Nitzschke, 28, were freed yesterday after being held for more than three months by a group called Ansar al-Tawheed wal Sunna (Followers of Unity and Prophetic Tradition).
The German government refused to confirm reports of a ransom and said it would give only a few details about the releases for fear there could be copycat kidnappings.