The bomb on Saturday struck a National Guard convoy at Abu Ghraib, home to the US prison, about 20km west of Baghdad, and also wounded 20 guardsmen, police said.
An attack on a US patrol in western Baghdad killed two civilians, police said. The US military said three American soldiers and seven Iraqi civilians were wounded.
A US vehicle and two Iraqi vehicles were destroyed, and the blast knocked down power lines, they said.
One Iraqi National Guardsman was killed and two were wounded by a roadside bomb at Yusufiya, about 75km south of Baghdad, police said.
And two car bombers killed themselves in an attack that wounded seven Iraqis on a road 10km south of the southern city of Basra, police said.
An Iraqi boy is taken to hospital
after a bomb attack in Baghdad
Late Saturday, mortars hit an Iraqi military base in southern Baghdad, injuring seven soldiers, police said.
In al-Haswah, west of Baghdad, a US soldier assigned to the 155th Brigade Combat Team, II Marine Expeditionary Force was killed when a roadside bomb exploded on Saturday near the convoy in which he was travelling, the US military said.
At least 1565 members of the US military have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.
A US soldier watches Iraqi men
during a traffic stop in Mosul
The US military said it had detained six Iraqi men in connection with the shooting down on Thursday of a commercial helicopter in which 11 people were killed, including six Americans.
The men were detained after tip-offs from Iraqi civilians. It was not clear where in Iraq they were found.
The Russian-built Mi-8 helicopter was shot down on Thursday as it flew over a deserted region north of Baghdad. Video footage shot by the attackers and broadcast by satellite channels showed it was hit by some sort of rocket or missile.
The three-member Bulgarian crew was killed as were six American private security contractors and two Fijian guards.
Meanwhile, Aljazeera has received a copy of a statement released by Muslims in Romania, calling on the captors of the Romanian journalists held in Iraq to follow Islamic principles and secure the captives' lives by releasing them soon.
The statement says abductions do not serve Islam, Arab nationalism or the Iraqi people's cause, and that the captives are victims of international policies, just as the Iraqi people are.
The statement came a day after the captors gave the Romanian government four days to withdraw its troops from Iraq.
Aljazeera broadcast a video it had received, showing the two men and a woman who were abducted on 28 March in Baghdad.
The captors are demanding
Romania withdraw from Iraq
Fariz Abd al-Majid al-Laqta, leader of the Islamic and Cultural League in Romania, told Aljazeera: "We Muslims living in Europe call on the captors of the Romanian captives to be committed to Islam's tolerant principles in war and peace, secure the lives of the journalists and treat them well.
"We also call on the captors to respond to Islam's calls, apply its principles and release the captives and their guard soon."