Medical officials said the bodies of seven people killed by the blast on Saturday and 59 wounded were brought to two Baghdad hospitals. Officials said most of the victims were policemen, but the identities of all the dead were not yet known.
The US military said two car bombs exploded at 9.30am (0630GMT) near a checkpoint leading to the heavily fortified area, which houses the offices of Iraq's interim government and several foreign missions, including the US embassy.
Only one blast was heard at the time, suggesting the bombs may have been timed to detonate simultaneously.
Bursts of automatic fire followed the thunderous explosions, which shook windows several hundred yards away in buildings on the opposite side of the Tigris River from where the attack occurred.
One survivor, policeman Rafid Khudair, described the moments before the explosion: "I was in the criminal investigation department and saw our guards open the gates for a police patrol. Then a white car followed them in and blew up outside our building," he said from his hospital bed, his head in bloody bandages.
On Friday night, a truck bomb exploded in the centre of the town of Tribil on the Iraqi border with Jordan, destroying a VIP hall mainly used by US forces.
The toll among US troops in Iraq
continues to rise almost daily
"Two multinational forces soldiers were killed and five wounded in a vehicle-borne explosion on the Iraqi side of the border crossing at Trebil," said Major Jay Antonelli.
Earlier, Lieutenant Lyle Gilbert said the marines opened fire on the suspicious truck as it headed towards them, but they were unable to stop it. It proceeded in the direction of the troops before blowing up.
On Friday, an explosion near a US patrol in Baghdad killed one soldier and wounded three others.
The military said on Saturday that the attack occurred in a northern district of the Iraqi capital, but provided no further details.
Also on Friday at least 26 people, including a dozen police personnel, were killed in two separate attacks north and west of the Iraqi capital.
Twelve Iraqi policemen were killed and 10 others wounded on Friday in an attack launched by an unknown group of fighters on al-Amal police station, near the airport road in western Baghdad.