US spokesman Master Sergeant Robert Powell confirmed the blast near the town of Balad on Sunday and said six national guardsmen were also wounded in the attack.


The dead civilian was a woman who had been standing on the roadside at the time of the attack, around 8am (0500 GMT).


Meanwhile, a second roadside bomb killed a US soldier and wounded another north of Baghdad, according to an army statement.


The US toll since Iraq's invasion in March 2003 is 1333.