The officials say the shootings happened Monday at Camp Liberty near Baghdad's airport.
One senior military official in Washington said it was not yet clear whether the shooter was among the dead. The official spoke on condition of anonymity because the circumstances surrounding the deaths are under investigation.
Initial reports indicated the Army soldier shot several others, then turned the gun on himself. But it was unclear whether he, too, had died.
THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.
WASHINGTON (AP) — A Pentagon official says a U.S. soldier killed five fellow troops at American base in Baghdad.
The five were killed in a shooting Monday afternoon, Baghdad time, at Camp Liberty near Baghdad International.
A senior military official in Washington says he has no other details on what happened. He spoke on condition of anonymity because the circumstances surrounding the deaths are under investigation.
The toll was the highest for U.S. personnel in a single incident since April 10, when a suicide truck driver killed five American soldiers with a blast near a police headquarters in the northern city of Mosul.
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