commanding troops who were brutalized by some of these shia militias i will not and i hope we never coordinate or cooperate with shia militias. >> reporter: the pentagon insists the ground offensive stalled when the militiamen proved unreliable. u.s. officials say air strikes were not started until baghdad took full control on the ground. but the reality may be different. >> you don't have an iraqi force that has complete control of all the forces that have been fighting. they have had some command of elements of that. it's been a hodgepodge of actors all contributing. >> reporter: now the iraqi forces the reality is they still cannot function on their own on the ground. they need those thousands of iranian backed shia militia to make further progress according to u.s. officials. it's a really interesting wrinkle. another wrinkle in that u.s./iran relationship. >> barbara starr, thank you so