we have nick paton walsh with the latest. what can you tell us about the american killed in the offensive? >> reporter: as is often in the opening 24 hours of the u.s. casualty in the field, there is little information available. we understand it may be an improvised explosive device. he was injured and medevac and died from injuries. we don't know despite the pentagon's line they are not involved in the assault, they are at the front and they are in the armored vehicles that move forward and we have seen twice the first wave of assault that actually heads into territory. a lot of fierce resistance. we saw yesterday and you can see the peshmerga trying to shoot down a drone they thought was sent to look at them from isis. this is a violent assault. it is not moving as quickly as