matt, what can you tell us from erbil? >> reporter: thanks, tamron. the situation now is three days in. we have seen a combined complex attack just like we have seen before. now this is a classic isis maneuver trying to divert attention away from the main battle in mosul to a city about nine hours south. that's effective. they are basically the mayor of the city that called on reinforcements. that's dragging military resources away from the main battle of mosul. the main objective. what this demonstrates is isis's ability to emerge in places that have been conquered already by iraqi military forces and divert attention from the main battle. there are so many positions behind the main lines in the fight for mosul that have so many isis elements in them. we saw in kirkuk they can raise up sleeper cells and attack with dozens of men with small arms