"The soldier died as a result of an injury," a brief statement issued by the US-led coalition forces said, without revealing further information on the incident, Alaraby news website reported.
But an Iraqi military source suggested the "American soldier was injured on May 3 during a battle at Tel Saqf Northeast of Mosul. One soldier was killed at the scene," he said.
"The soldier that died on Sunday was one of two that were injured during the battle."
This is the second loss for the US in Iraq in one week.
Last week, a US soldier was killed near Erbil in Iraq, as the ISIS terrorist group launched a new offensive against Kurdish Peshmerga forces in the region.
The soldier was killed while performing his duty as an adviser to Kurdish Peshmerga troops in the North of the country.
There are ongoing clashes on battlefronts between the cities of Mosul and Erbil, with ISIS militants using a large number of suicide bombers against Peshmerga forces.
Sources on the ground confirmed that US troops were fighting alongside the Peshmerga forces, with air support coming from the international coalition, to repel ISIS from the town.
Peshmerga fighters of Iraq's autonomous Kurdish region have been heavily involved in the campaign against ISIS in Northern Iraq.
The US government has been pressing the effort against ISIS, which has been slowed down in its quest to overrun Iraq, FNA reported.
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