A roadside bomb attack on a bus filled with Iraqi troops on a road between Tikrit and Baiji, north of Baghdad, killed at least 23 security personnel.
In the north-western town of Tal Afar, a car bomb killed three more Iraqi soldiers and wounded four other people while a British soldier was killed in a mortar attack on an army base in the southern city of Basra.
In Baghdad, a suicide bomber in a car targeted soldiers collecting their salaries from a bank, killing at least 10 people, including an elderly woman. State television put the death toll at 14.
The blast was in the same spot in Karrada district where a car bomb and mortars killed at least 27 people last week.
"We should carry guns to protect ourselves. If we expect Iraqi security forces to protect us we will burn, just like those innocent people," said kiosk owner Abu Fadhil, surveying charred bodies.
"The government is useless. Only days ago we suffered from a huge blast here. The interior minister has to admit they lost the war against the terrorists."
A boy, about 12-years old, stood in the street sobbing and tearing his shirt after seeing his dead mother. "My mother, my mother, my mother," he screamed.
US to boost troop levels
Two months after being sworn in, Iraqi Prime Minister Nuri al-Maliki has yet to prove he can end such carnage and sectarian bloodshed which has raised fears of civil war.
He has presented a 24-point reconciliation plan that is long on promises and short on details, and imposed a security crackdown in Baghdad that has proven ineffective.
The army casualties served as a reminder that US-trained Iraqi forces have a long way to go before they can handle security on their own and allow Washington to bring home troops.
The United States plans to boost its troop levels in Baghdad and
National Security Adviser Mowaffaq al-Rubaie said extra Iraqi brigades would also be brought to the capital.
A few hours after he spoke several mortar bombs landed at the fortified Green Zone government compound, police said.
The body of Adel al-Mansouri, a correspondent for al-Alam television station, was found dumped with bullet holes on a street.
Iraqi security forces were also targeted in the town of Muqdadiya, 90km north-east of the capital where a car bomb exploded as a police patrol passed in front of a hospital, killing at least seven people.
In the northern oil city of Kirkuk, a roadside bomb killed two police and wounded a third as they conducted a patrol.