WASHINGTON (AP) – A top U.S. commander says the United States probably played a role in the deaths resulting from a March 17 airstrike in Iraq.

But Lt. Gen. Stephen Townsend, the commander leading the fight against Islamic State militants, says it appears enemy fighters may have gathered the civilians into the building for use as human shields.

Witnesses say the strike may have killed at least 100 people.

Townsend said Tuesday there is a “fair chance” the U.S. launched the strike.

He says U.S. personnel have visited the site to conduct tests and gather information. But he says the munitions used by the U.S. should not have been able to bring down the entire building, raising questions about U.S. involvement.

U.S. airstrikes are targeting IS fighters to help Iraqi forces retake Mosul.

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