According to Iraqi police sources on Sunday, a bomber with explosives strapped to his body blew himself up at the Muthana airport recruitment centre which had already been targeted on previous occasions.
One police source said 21 were killed and 31 wounded, though a doctor at a nearby hospital said it was treating 34 wounded and had received many dead.
Meanwhile, a car bomber in the northern city of Kirkuk has killed three Iraqi officials and wounded 10 more at a local authority building.
Police spokesman Colonel Yadigar Muhammad said he did not know why the municipality building had been targeted.
The municipality is controlled by Iraqi President Jalal Talabani's Patriotic Union of Kurdistan, one of two Kurdish factions in northern Iraq.
Eight members of the same Iraqi family, including a two-year-old, were shot to death in their sleep early on Sunday, police said.
The father suspected it was a sectarian crime.
Three Iraqi officials were killed in
the Kirkuk attack
Residents of the eastern Baghdad neighbourhood Baladiyat discovered the bodies early on Sunday, said Colonel Ahmad al-Alawi, the director of al-Rashad police station.
The eight - seven siblings and their mother - died of gunshot wounds, he said. Six of the dead were aged between two and 14 years. One boy was injured.
The father, Hussain al-Tarash, was not home at the time of the killings.
"This is because we are Shia. I have no enemies", a distraught al-Tarash told reporters. "We have no political leanings."
Another report quoted a police officer as saying that "It's a terrorist operation; but I can't tell you anything more. We found a total of 45 pistol and Kalashnikov spent casings.
"The front door had been broken in and all of the victims were found in their beds, except for one 18-year-old boy, Nasser, who must have tried to fight them off as he was lying on the ground in a hallway," the policeman added.
A nearby shopkeeper said a relative of the family came by in the morning and knocked for 15 minutes at the garden gate.
"He then stopped a police patrol and told them: 'This house is full of people and no one is answering the door.'
"Police called for reinforcements and then discovered the ghastly scene," he said.
- Two employees of Iraqna mobile phone company were killed on Sunday morning while on their way to work, Iraqi police sources said.
- A blast on Sittin street in Dora area south of Baghdad targeted at a US military patrol destroyed a Hummer vehicle and injured at least four US soldiers, Iraqi police and eyewitnesses said.
- Also in Baghdad, some explosions were heard in Salman Faiq street in the centre of the city.They were targeted at the police directorate there. However, there are no reports of casualties so far.
- Fierce clashes have also erupted between fighters and US patrols near the city hall in Sidiya area south of Baghdad. The city hall building had previously been destroyed by the fighters. Again, no casualties have been reported.