In a statement, the US occupation forces said the soldier was killed when a roadside bomb was detonated as their convoy drove near the town west of Baghdad.
Earlier, in the town of Arbil, the deputy security chief of the Kurdistan Democratic Party (KDP), the former rebel faction ruling Arbil, was wounded and his three bodyguards killed in an ambush outside his home, police said on Sunday.
The KDP number two security official Jawamir Attiyah Kaki was taken to hospital, said Arbil's police chief Nariman Abd al-Hamid.
"It happened at 8:25 am (05:25 GMT) in the morning as he was leaving his home in the Runaki district in the south of the city.
Assailants opened fire with automatic weapons, wounding him and killing his three bodyguards," Abd al-Hamid said.
Captain Jason Beck, a spokesman for the US First Armoured Division, said five US soldiers, eight members of the Iraqi Civil Defence Corps and an Iraqi interpreter were also wounded in the Baghdad explosions, which occurred in a busy shopping district.
"One soldier was killed and five wounded in a double IED (improvised explosive device) blast," the spokesman said.
The wounded were taken to a hospital, but no further details were available, he said.
US occupation soldiers are coming
under regular attack across Iraq
The latest death raises to 212 the number of US soldiers killed in action since US President George Bush declared major hostilities over on 1 May.
Meanwhile, a fifth Bulgarian soldier died of his wounds, following an attack on occupation troops on Saturday in the town of Karbala. Two Thai soldiers died in the same attack.
In another attack two Iraqis are believed to have been killed and a Briton may have been wounded in an attack south of Baghdad on Sunday, the US-led occupation force claims.
"It's really sketchy, I think there was small arms fire involved", said a military spokesperson.
The US led occupation Coalition Provisional Authority ruling Iraq claimed late on Sunday that it had recieved unconfirmed reports that a British contractor may have been wounded in Baghdad.
"I think two Iraqis were killed" in the incident at Ziyana south of the capital, the spokesperson added.
A group pf sub-contractors had been working for the US Army Corps of Engineers in Ziyana.
In the north of the country unknown attackers opened fire at the offices of a US non-governmental organisation in Kirkuk late on Sunday, killing an Iraqi security guard, police said.
Adel Omar Ali was on duty outside the offices of the Research
and Training Institute (RTI) in the centre of the city, police
officer Amer Hamdane told AFP.
The RTI works with the US-led Coalition Provisional Authority