Al-Jazeera television said that an American soldier was executed by the Iraqi militants because the U.S. government did not change its policy in Iraq. There are no immediate comments from U.S. officials.
Pfc. Keith M. Maupin of Batavia, Ohio was captured in April during an ambush on a convoy west of Baghdad.
The Arab satellite station showed video showing a blindfolded person sitting on the ground but did not show the killing.
The station said the militants shot him.
Maupin was married and had a one-year-old child.