Iraqis have stepped up attacks
against their occupiers
One soldier was shot and killed while on patrol in the town of Balad, some 90 kilometres north of the capital Baghdad.
US military officials did not reveal when the incident took place and said they had no further details on the incident.
The area around Balad is under the control of the US Army's 4th Infantry Divison.
Meanwhile, a female US soldier was fatally shot late on Monday in the town of Alramadi 110 kilometres west of Baghdad, reported Aljazeera.
A second soldier was injured. US Central Command in Tampa, Florida said it had no information of the incident.
The shooting came after US forces opened fire at protesters in Alramadi, killing at least three Iraqi civilians and injuring others including children.
Residents were demonstrating against US occupation forces storming homes and mosques in search of alleged weapons. People said they were also prevented from praying at the mosque.
Sunnis and Shia protest hand in
hand against the arrest of an Imam
Meanwhile, thousands of Iraqis took to the streets of Baghdad on Tuesday in protest over the US arrest of a Shia dignitary.
American troops detained Sheikh Jassem Alsaadi, a popular Imam, "without any reason" on Monday before releasing him, said Sheikh Hazem Almayali.
Almayali called for an immediate end to the occupation forces' searches of homes. Protesters carried banners calling for a US withdrawal and vowed to stand united.
"Sunnis and Shia united against American occupation," read one banner. Demonstrators said the protest was a warning before they step up resistance attacks.
Protesters also urged for the immediate creation of an Iraqi national government.
Tensions are rising as Iraqis grow more frustrated with their occupiers. The US administration in Iraq announced on Monday it would cancel a long-promised national conference and instead appoint an advisory body that will act as a fledgling government.
Since US tanks rolled into the heart of Baghdad in April, Iraqis have stepped up resistance attacks, killing and wounding several dozen soldiers.