Updated

The top Army officer says it will become increasingly difficult to target and launch precision airstrikes against Islamic State militants hiding among the Iraqi population.

Army Chief of Staff Gen. Ray Odierno (oh-dee-EHR'-noh) says the worst thing that could happen is if the U.S. begins mistakenly killing innocent civilians, causing the population to turn against the U.S.-led effort against the Islamic State group. He says Iraqi or other ground troops may be needed to better direct the strikes.

Odierno says the U.S. will determine over time whether it can maintain the precision of the strikes, or if additional ground support is needed. U.S. leaders have ruled out fighting a ground war in Iraq, but they've left the door open for specialized troops to embed with and advise Iraqi units.