The attack, which the US army said occurred late on Saturday evening, brought to 150 the number of US soldiers killed in action since President Bush declared major combat over on 1 May.
"One soldier was killed and another was wounded in an improvised explosive attack at 7:45 pm" in Baghdad's Waziriyah neighbourhood, a military spokesman told AFP.
Earlier on Saturday, two soldiers from the 82nd Airborne Division were killed and one wounded by a roadside bomb in the town of Falluja, west of Baghdad.
On Friday, six US soldiers were killed when a Black Hawk helicopter was brought down by resistance guerillas, as confirmed by the US military.
"We do believe it was brought down by ground fire," Lieutenant-Colonel Steve Russell told Reuters on Saturday, speculating it was hit by a rocket-propelled grenade (RPG). It was the third US helicopter to be shot down in Iraq in the past two weeks.
Following the incident, US warplanes launched a bombing strike on areas surrounding the Iraqi city of Tikrit, signalling a possible change in tactics by occupation forces.
“This time, US warplanes, rather than helicopters, have launched the strike, making it different from other US military operations in Iraq”, Aljazeera correspondent Aktham Sulayman reported.