BAGHDAD, Iraq (CNN) -- The person who attacked a U.S. military base in Mosul was likely wearing an Iraqi military uniform and carried a bomb in a vest, Brig. Gen. Carter Ham, U.S. commander in Mosul, told CNN Thursday.
Ham said the investigation into the deadly attack continues but it appears the bomb was detonated inside the Camp Marez mess hall. The explosion killed 22 people, including 14 American soldiers.
Ham also said that providing security for the planned January 30 elections will be difficult because of existing problems with Iraqi forces.
"I have enough U.S. boots on the ground. I do not have enough Iraqi boots on the ground," he said. "The development of Iraqi security forces has not been as fast as any of us would have liked."
If the investigation concludes that a uniformed Iraqi soldier detonated the bomb, the training process could be further complicated.
The Pentagon is investigating how U.S. forces check the backgrounds of Iraqis who work at U.S. installations.
A military spokesman said Iraqi workers have to show identification to gain entry to American facilities -- but they are not always searched, nor are they always escorted once allowed to enter.
Iraqis were helping in the construction of a permanent mess hall at Camp Marez.