basically break the perimeters and take over these towns. what more you can tell us, ian, about those methods, and are authorities able to stop this? >> reporter: well, that's been a very successful tactic of isis, in their campaigns are using these very heavily armored vehicles, bull dozers, trucks, packing them with explosives and then driving them right at the front lines of the iraqi military, or in northern iraq against kurdish forces. and they have been able to blow them up, create chaos, go after them, and push back iraqi forces, now, there were tens of these attacks when they finally were able to take ramadi. it's been described as mad max-tile of attacks. the united states has recognized this, they've sent anti-tank missiles to help the iraqi forces to stop these sorts of attacks. but as we speak, isis still