A Baghdad restaurant popular with the police, a Shia mosque, and the home of a community leader near Mosul were among the sites that came under attack on Monday.
Armed men also killed a senior Iraqi general in the capital on Monday, and the US military reported that four American soldiers were killed in combat earlier on Sunday in northern Iraq, while a fifth died in an accident.
In Monday's deadliest attack, two car bombs exploded in the town of Tal Afar, 80km west of the northern city of Mosul, killing at least 20 people and injuring 20 more, officials said.
The blasts apparently targeted the home of Hasan Baktash, a Shia Muslim with close ties to the Kurdistan Democratic Party.
In the second strike on the same day, a bomber blew himself up outside a Shia mosque shortly before evening prayers in Mahmudiya, a town 30km south of Baghdad.
Police said they killed at least 10 people and wounded 30 - many of them children.
About 610 people, including 49 US troops, have been killed since 28 April, when Prime Minister Ibrahim al-Jaafari announced his new government.
In Baghdad's worst attack in recent days, a car bomb killed at least eight people and wounded more than 80 when it exploded at lunchtime outside the Habayibna restaurant in the Talibia neighbourhood. It is a popular gathering spot for police.
Baghdad hospitals, where the dead were taken, did not say if any were police officers or soldiers.
A car bomb in Baghdad targeted
Iraqi policemen at a restaurant
"We were eating at the restaurant. Then I don't remember anything until I woke up here in the hospital.There were hundreds of people in the restaurant having lunch," said Dia Hamid, who was being treated at al-Kindi Hospital for head and stomach injuries.
A bomber killed five Iraqis and injured 13 when he drove an explosives-packed pickup truck into a crowd outside a municipal council office in Tuz Khurmatu, 90km south of the northern city of Kirkuk, a police commander, Lieutenant General Sarhat Qadir, said.
Monday's violence began in Baghdad when Major-General Wail al-Rubai, a senior official in the National Security Ministry, was killed along with his driver in a fusillade of automatic weapons fire from two cars packed with fighters.
Al-Qaida in Iraq, the group run by Jordanian Abu Musab al-Zarqawi, claimed responsibility.
The killing came a day after another senior government official, Trade Ministry auditing office chief Ali Musa, was shot dead.
Fighters have killed 18 officials since late April, nearly all in drive-by shootings.
In other violence during the day, two Iraqis were killed and two injured in Kirkuk when a mortar round hit a house, police Captain Farhad Talabani said.
US base attacked
In Samarra, north of Baghdad, three bombers trying to attack a US base wounded three soldiers, the US military said. Two Iraqi men were killed and 20 people, including men and women, were wounded, the police said.
Five US soldiers have died in
separate attacks since Sunday
The US military announced that three American soldiers were killed on Sunday and one wounded in two separate attacks in Mosul, 360km northwest of Baghdad.
Another soldier was reported killed when his patrol was hit by a car bomb just north of Tikrit, 130km north of the capital, and a fifth died in a vehicle accident in Kirkuk.
Meanwhile, US and Iraqi forces detained at least 428 people, they say are suspected fighters in, their biggest joint offensive in the Baghdad area.
Operation Squeeze Play, the largest ever joint Iraqi-US campaign in Baghdad, was launched late on Sunday to catch suspected fighters responsible for attacking the Abu Ghraib US-detention facility and the road linking downtown to the international airport.
Also on Monday, the bodies of brothers Haidar and Raid Jaffat were found in Latifiya, and three other slain men were dumped in Mahmudiya, police said. All had been shot in the head.