Shiite politicians and American soldiers that left at least 29 people dead.
The first attack took place in former Iraqi dictator Saddam Hussein's hometown of Tikrit around 9 a.m. local time. A suicide bomber posing as a police lieutenant gained entry inside a main police compound by flashing a fake badge to security guards at the front gate. The bomber then drove a white Oldsmobile into the police station's parking lot before setting off a massive explosion.
The blast set ablaze at least 20 other vehicles and an Associated Press photographer at the scene saw at least 10 charred bodies on the ground.
The suicide attack occurred when police officers were arriving to relieve colleagues working the night shift.
"He waited until the shift change, then he exploded the car," Police Col. Saad Daham said.
Daham blamed the front gate security guards for failing to check the bomber's identification papers or conduct a vehicle search. U.S. troops respondent by setting up checkpoints around Tikrit to search for other potential attackers.
But the Tikrit blast was only the deadliest in a spate of attacks. In northern city of Kirkuk, insurgents ambushed a police patrol where two officers were killed and three were wounded in a roadside bombing.
In Iskandariyah, two police officers died when a suicide bomber attacked their convoy. A child walking down the road was also killed in that attack.
Elsewhere, in Hilla, a suicide bomber exploded his vehicle in front of the headquarters of the Supreme Council for the Islamic Revolution, the leading Shiite political party, killing seven and wounding another eight.
And in an area north of Samarra, two U.S. soldiers were killed and two were wounded in a roadside bombing.
The wave of violence comes a day after current interim Prime Minister Iyad Allawi announced that his party, the Iraqi National Accord, was forming a coalition to challenge the Shiite's leading candidate Ibrahim al-Jaafari.
The United Iraqi Alliance, a major Shiite coalition, nominated interim Vice President al-Jaafari for prime minister after Ahmad Chalabi withdrew his candidacy.
In announcing the creation of his coalition, Allawi, a secular Shiite, said, "We believe in a liberal Iraq and not an Iraq governed by political Islamists." Some fear al-Jaafari could lead Iraq toward an Islamic theocracy or even a strictly sectarian Shiite one.
Allawi's party faces a major uphill battle against the Shiite coalition, which holds 140 seats in the National Assembly. The interim prime minister will need the support of the Sunnis, Kurds and secular Shiites to win any nomination.
Iraq's next prime minister will be responsible for overseeing the drafting of a new constitution even while combating ongoing insurgent violence.