The latest fatality occurred Wednesday in Babil province, part of an area known as the "Triangle of Death" because of the frequency of insurgent attacks on U.S.- and Iraqi-led forces there.
In eastern Baghdad, two suicide car bombs exploded outside the Interior Ministry, killing at least two policemen and wounding five others, police Maj. Jabar Hassan said. Officials at nearby al-Kindi hospital said 15 people were injured in the blasts.
Hassan said the car bombers were trailing a police convoy that was trying to enter the ministry. Iraqi security forces opened fire on the vehicles and disabled them before they could arrive at a main checkpoint outside the building, said Col. Adnan Abdul-Rahman, an Interior Ministry spokesman.
"Casualties were very small because they didn't get to the checkpoint," Abdul-Rahman said.
Another car bomb exploded in Baqouba, 35 miles northeast of the capital. There has been no word on casualties.
In other recent developments:
Talks aimed at forging a new coalition government faltered Wednesday over Kurdish demands for more land and concerns that the dominant Shiite alliance seeks to establish an Islamic state, delaying the planned first meeting of Iraq's new parliament.
The snag in negotiations between Shiite and Kurdish leaders in northern Iraq came as clashes and two other car bombings in Baghdad on Wednesday killed at least 14 Iraqi soldiers and police officers - the latest in a relentless wave of violence since elections Jan. 30.
The group led by Iraq's most wanted terrorist, Abu-Musab al-Zarqawi, purportedly claimed responsibility in an Internet posting for Wednesday's clashes and at least one of the bombings - as it had for a suicide car bombing Monday that killed 125 people in Hillah, a town in Babil province south of the capital.
National Security Adviser Mouwafak al-Rubaie vowed the attacks would not derail the political process. "The Iraqi government will go after and hunt down each and every one of these terrorists whether in Iraq or elsewhere," he said.
The U.S. soldier, assigned to the 1st Marine Expeditionary Force, was killed in action "while conducting security and stability operations," the military said, adding that the release of more details could place U.S. troops at "greater risk."
U.S. troops are killed nearly every day in Iraq.
The latest death brought to at least 1,500 the number of members of the U.S. military who have died since the U.S.-led war in Iraq began in March 2003, according to an Associated Press count. At least 1,140 died as a result of hostile action, according to the Defense Department. The figures include four military civilians.
Since May 1, 2003, when President Bush declared that major combat operations in Iraq had ended, 1,362 U.S. military members have died, according to AP's count. That includes at least 1,030 deaths resulting from hostile action, according to the military's numbers.
The tally was compiled by The Associated Press based on Pentagon records and AP reporting from Iraq.