Officials were quick to blame insurgents linked to al-Qaida in Iraq for the shootings in the capital, saying the militants were redoubling efforts to destabilize the country at a time of political uncertainty over who will control the next government.
Shiite Vice President Adel Abdul-Mahdi stressed the importance of quickly forming a government that does not exclude any major political group to try to prevent insurgents from exploiting Iraq's fragile security.
"The terrorist gangs perpetrated new assaults today on our people and armed forces," he said. "We call on all political blocs to work seriously for the benefit of the country and ... start to form a national partnership government including all political parties without marginalizing any one."
More than two months after the March 7 election, Iraq's main political factions are still struggling to put together a ruling coalition. Prime Minister Nouri al-Maliki's Shiite bloc has tried to squeeze out election front-runner Ayad Allawi -- a secular Shiite who was heavily backed by Sunnis -- by forging an alliance last week with another religious Shiite coalition. The union, which is just four seats short of a majority in parliament, will likely lead to four more years of a government dominated by Shiites, much like the current one.
Sunni anger at Shiite domination of successive governments was a key reason behind the insurgency that sparked sectarian warfare in 2006 and 2007. If Allawi is perceived as not getting his fair share of power, that could in turn outrage the Sunnis who supported him and risk a resurgence of sectarian violence.
The relentless cascade of bombings and shootings -- hitting at least 10 cities and towns as the day unfolded -- also raised questions about whether Iraqi security forces can protect the country as the U.S. prepares to withdraw half of its remaining 92,000 troops in Iraq over the next four months.
The U.S. and Iraq have claimed major blows again al-Qaida in Iraq over the last month -- most notably the killings of two militant leaders Abu Omar al-Baghdadi and Abu Ayyub al-Masri in an April 18 raid on their safehouse near Saddam Hussein's hometown of Tikrit.
But U.S. Maj. Gen. Stephen Lanza, the top military spokesman in Iraq, said Monday's attacks show "there is a threat out there that we have to be concerned about, and the threat is still capable."
The violence began before dawn in Baghdad in a series of attacks against checkpoints and patrols, targeting security forces. Gunmen disguised as cleaners used weapons fixed with silencers to spray security forces with bullets. At least 10 people were killed.
Most of the day's casualties were in two Shiite-dominated cities where wounded victims screamed their fury at the government for failing to protect them.
The worst violence hit the Shiite city of Hillah, the capital of Babil province 60 miles (95 kilometers) south of Baghdad. First, two parked car bombs near a textile factory exploded as workers were leaving the factory around midday, said Babil provincial police spokesman Maj. Muthana Khalid.
Then as rescuers and workers were trying to help the injured, a suicide attacker with explosives strapped to his body blew himself up in the crowd.
At least 45 people were killed and dozens more injured, according to Khalid and al-Hillah hospital director Zuhair al Khafaji.
"It was a horrible scene with human flesh and blood on the ground," said Jassim Znad Abid, a taxi driver who lives in Hillah. "I saw dead people, some burned and crying, wounded people on the ground that was covered with pools of blood."
Babil provincial Gov. Salman Nassir al-Zargani ordered flags lowered to half-staff and a three-day mourning period. In an interview with Iraqi state TV, he said he was informed Sunday that the factory was under threat, but cited too many security gaps across Babil to protect all sites he feared could be targeted.
"There are many fragile places especially in the north of Babil... and there are a lot of security gaps there," he said. "So we are facing a daily challenge in Babil."
Hillah has been the site of horrific bombings in the past, including blasts in 2007 that killed at least 120 people and a suicide car bomber in 2005 that killed 125 people, mostly police and national guard recruits.
In another Shiite city, the southern port of Basra, three bombs, including one that targeted a marketplace, killed at least 16 people, hospital and police officials said. Basra has been relatively quiet since the days when Shiite militias allied with Iran ruled the streets; al-Maliki, with heavy U.S. support, routed the militias in 2008.
A pair of bombs struck the small town of Suwayrah, 25 miles (40 kilometers) south of Baghdad, killing 11. Three different bombings in the town of Abu Ghraib west of Baghdad that killed at least six people.
Twelve more were killed in five separate attacks stretching from the northern city of Mosul to the western city of Fallujah in Anbar province to the Shiite city of Musayyib south of Baghdad.
The attack in Mosul killed at least two people near a checkpoint run by Iraqi security forces, Kurdish security forces known as the peshmerga, and U.S. troops. The joint checkpoints were set up earlier this year under U.S. supervision as a way to get Iraqi and Kurdish forces working together in areas claimed by both the Kurds and Iraq's federal government.
Daily violence in Iraq has eased since the height of the insurgency. But the latest attacks raise fears that the country's barely contained sectarian tensions could once again explode -- especially at a time of clouded political leadership. However, there have been few, if any, examples if the retaliatory violence that marked the sectarian conflict just a few years ago and brought Iraq to the brink of civil war.
On Monday, Allawi told reporters he has been trying for days to meet with al-Maliki and begin hammering out a compromise, but to no avail. He vowed to fight attempts to overturn the election results and called for an end to efforts to disqualify some of his Iraqiya coalition's winning candidates.
"We won't stand still if the harm against Iraqiya continues," Allawi said.