correspondent chris lawrence and our international correspondent in kabul on breaking news four americans have been killed at bagram air base. let s start with you, chris. what have pentagon officials told you? this was supposed to be a day where u.s. officials were highlighting the fact they were stepping back from the front lines in afghanistan. instead, they re now trying to explain how at least two more american service members have been killed. sources are saying this was an indirect fire attack in eastern afghanistan. that suggests that it could be a mortar attack or rpg attack. we know at least two of the dead are u.s. service members. four casualties in all. jake? and raza, what are you hearing there? we just got off the phone with isaf officials. they re not revealing anything other than what chris just told us. they said it happened late last night. it s 3:00 in the morning right now. so we know it didn t happen within the past three hours.