American troops have been injured in the past six to eight weeks assisting Iraqi forces in the effort to retake the Islamic State stronghold of Mosul, CNN reports.

"Yes, they have been under fire at different times," coalition spokesman Col. John Dorrian said Tuesday during a press conference at the Pentagon. A Defense Department official told CNN that some U.S. troops have been injured, but would not give a specific number.

"They have come under fire at different times," Dorrian said. "They have returned fire at different times in and around Mosul. That has happened at different times."

He said American troops try to avoid becoming involved in firefights, but do shoot back when fired upon.

"When someone is shooting at you, that is combat," Dorrian said. "Yes, that has happened."

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