The country's new leadership, due to assume sovereignty in five days, claimed much of the unrest was directed by foreigners but offered no proof.
"Our culture, our customs have been destroyed," interim Defense Minister Hazem Shaalan told reporters. "The time has come for a showdown."
The interim vice president warned that a drastic deterioration in the country's security could result in the implementation of emergency laws or martial rule — however undesirable such measures may be in a democratic society.
"Announcing emergency laws or martial law depends on the nature of the situation. In normal situations, there is clearly no need for that (step)," Ibrahim al-Jaafari said.
"But in cases of excess challenges, emergency laws have their place," he said, adding that any such laws would fall within a "democratic framework that respects the rights of Iraqis."
Meanwhile, the U.S. military launched its third airstrike in a week Friday targeting Abu Musab al-Zarqawi's network in Fallujah, using precision weapons to hit a suspected safehouse. The Jordanian-born terrorist claimed responsibility for Thursday's attacks.
In other developments:
Earlier Friday, U.S. tanks and armored vehicles maneuvered on the highway near the edges of Fallujah, firing in all directions, while armed men in an eastern suburb returned fire, witnesses said.
Hours later, a roadside bomb exploded in a residential neighborhood in Baghdad, killing one Iraqi policeman and wounding another, police said.
Outside the capital, American forces set up checkpoints around Iraq to intercept weapons, guerrillas and bombs.
U.S. commanders are said to be reluctant to see martial law imposed, since the large contingent of U.S. troops would almost certainly be required to enforce the policy, which could include widespread searches of private homes and bans on peaceful demonstrations.
Those actions would be hard to reconcile with one justification for the Iraq invasion: that it would bring freedom and democracy to a totalitarian regime.
The insurgent assaults were launched in the morning on Thursday, when black-clad guerrillas attacked police stations and government complexes in Baghdad, Baqouba, Mosul, Ramadi and Mahaweel. U.S. troops and insurgents traded heavy fire on the outskirts of Fallujah, where explosions were also heard early Friday.
The heaviest fighting was in Baqouba, northeast of the capital, where guerrillas shot their way into a government office complex, seized two police stations and destroyed the home of the provincial police chief. The stations were recaptured Thursday afternoon, said Maj. Neal O'Brien of the 1st Infantry Division on Friday.
Two American soldiers died in the Baqouba fighting, the 1st Infantry Division said.
Insurgents also attacked a police station in a Baqouba suburb late Thursday, killing three officers and injuring one, said Dr. Nassir Jawad, who is in charge of the Baqouba morgue. Isolated skirmishes were also reported nearby into Thursday evening, O'Brien said Friday.
But the day's worst bloodshed came in Mosul — the country's northern metropolis often touted as a success story in restoring order in Iraq — where the U.S. military said 62 people were killed, including a U.S. soldier, and more than 220 people were wounded.
Most died when at least four car bombs rocked the police academy, two police stations and the al-Jumhuri hospital.
U.S. troops recaptured the Sheik Fathi police station in a hail of gunfire, and Iraqi troops raided a nearby mosque used by insurgents, the U.S. military said. Mosul's governor imposed an overnight curfew.
Three U.S. soldiers were among the dead on Thursday. At least 320 people were wounded, including 12 Americans.