showing of this bomb, this 21,000-pound-plus bomb being dropped yesterday in a mountain valley in afghanistan. this underscores the u.s. military effort to go after isis in that country. they say the target was an isis complex of tunnels and caves, that they were trying to go after. the top u.s. commander in afghanistan held a press conference a short time ago, and he underscored the point, it was about his military objectives and not something else. >> we had persistent surveillance over the area before, during and after the operation, and now we have afghan and u.s. forces on the site and see no evidence of civilian casualties nor have been theren in any reports of civilian casualties. >> general mickelson going on, no outside events influencing his thinking. somewhat pushing back against