WASHINGTON (AP) — The top U.S. military officer says the U.S. called in Apache helicopters to prevent Iraqi forces from being overrun by Islamic State militants in a recent fight near Baghdad’s airport.

Gen. Martin Dempsey says the extremists were within about 15 miles and had they overrun the Iraqis, “it was a straight shot to the airport.”

The Joint Chiefs of Staff chairman also tells ABC’s “This Week” that there could be circumstances in the future when a no-fly zone over Syria could be part of the military campaign.

Dempsey says there may come a time when he might recommend that American advisers accompany Iraqi troops against Islamic State targets. Dempsey thinks Mosul, in northern Iraq, could be the “decisive” battle in the ground campaign at some point.

Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.