stronghold in iraq, mosul. they've routed militants from nine nearby villages. u.s. troops will be heavily involved in this effort to take back mosul and the pentagon admits that could put americans in harm's way. nick paton-walsh is with peshmerga fighters on the road to mosul. hi, nick. >> carol, as you said, we saw yesterday, as the first peshmerga convoy moved over the barriers they had separating them from isis towards the main road behind me here, now actually enveloped in a pretty thick cloud of black smoke. we're not sure what it's from. maybe an oil fire, an air strike. always hard to tell. as that peshmerga convoy moved down the road, it was pretty clear there were foreign troops with them. we saw vehicles distinctly associated with the american armed forces. they were part of that convoy. they disappeared into the front ranks. so it's unclear quite what their role was. they may well have been involved in helping some of the air power here that's being coordinated. very effective against isis so