The attack, which also wounded an Iraqi civilian, occurred on Friday in the Abu Ghraib district, the US military said in a statement on Saturday.
The identity of the soldier who was killed was not released pending notification of his family.
No further details were immediately available.
As of Saturday 11 December 2005, at least 2137 members of the US military have died since the invasion of Iraq in March 2003 by US-led forces, according to an Associated Press count.
At least 1676 died as a result of hostile action, according to US military figures.
The figures include five military civilians.
Attacks against US and Iraqi forces across the country have intensified recently, with an Iraqi soldier being killed and 10 others wounded in the town of Balad.
US soldiers in Falluja held a
memorial for fallen colleagues
In Tikrit, police said an armed group kidnapped an Egyptian national who was said to be working with US troops in the area.
US and Iraqi forces in the city have arrested 52 civilians alleged to be members of so called armed groups in the past 48 hours.
In Mosul, two Iraqis were killed and a third injured in a car bomb attack targeting a US military patrol. The US military vehicle was destroyed in the blast. US soldier assigned to the 155th Brigade Combat Team, II Marine Expeditionary Force, died of a suspected heart attack while on guard duty at a base near the town, the US announced on Saturday.
In Falluja, a
The marines said the soldier died on 8 December. The soldier's name was being withheld pending notification of next of kin.
Deadline for captives
Saturday is the deadline given to London and Washington to free all prisoners held in Iraqi and coalition prisons or the four foreign nationals held captive would be killed, the so-called Brigades of the Swords of Righteousness in Iraq said.
American Tom Fox, 54, Briton Norman Kember, 74, and their Canadian colleagues from the Christian Peacemakers Team (CPT), James Loney, 41, and Harmeet Singh Sooden, 32, were kidnapped in Baghdad two weeks ago.
"In the name of all Muslim Brothers, I solicit the kidnappers ... to let them free without delay, and to safeguard their bodies and souls"
Muhammad Mahdi Akif,
head of Egypt's Muslim Brotherhood
Missing in addition to an abducted German mother, French engineer and an American security contractor, the resurgent hostage crisis underscores the chaos in Iraq ahead of Thursday's elections to elect a full-term parliament.
Footage showing two men wearing orange jumpsuits similar to those worn by detainees at the US Guantanamo Bay prison, bound by shackles and handcuffs and their faces obscured, was shown on Aljazeera television late on Thursday.
Government officials and religious leaders from around the world have appealed for their release.
The head of Egypt's Muslim Brotherhood movement, Muhammad Mahdi Akif, became the latest dignitary to deliver an appeal for their freedom.
"In the name of all Muslim Brothers, I solicit the kidnappers ... to let them free without delay, and to safeguard their bodies and souls," he said in a statement issued by the Christian Peacemakers Team.
"They belong to a Christian organisation that loves peace... The likes of those should be welcomed by the Iraqi people, and their presence should be supported," he added.
CPT colleagues along with family members pleaded for mercy, stressing that their colleagues had been working to restore justice and human rights in Iraq.