One US soldier was killed by a sniper in Baghdad, and 19 others were wounded in another incident near the town of Balad, north of the capital, said the US military.
At least 18 US soldiers have been killed since US President George Bush said the biggest part of the fighting was over on 1 May.
Reward for Saddam's capture
At the end of June six British soldiers were killed in the south of Iraq.
Supporters of former Iraqi President Saddam Hussein have been blamed for the attacks.
President Bush said anyone with information about where Saddam is could get a £15m reward from the US.
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