now we understand that there an explosion, there has been an explosion in the pentagon, the heart of the military command centerlarge airliner, perhaps hijacked, perhaps part of some widespread plan. apparently slamming into at least the area around the pentagon. [sirens] they have not struck at america. they have struck at some individual places in america but, this country will go on. i want to go to our washington managing editor brit hume who has the outlook from the nation's capitol. brit, this raises all kinds of questions about america's response, and i guess that response is not going to be immediate, is it? >> whether it is immediate or not, one thing we're seeing, jon, this series of evacuations from various buildings around washington. i think it is important to say that we don't know, we have no reason to believe, the white house, for example, was facing any immediate or imminent threat. the same true on capitol hill. it appears they're evacuating building up here soon. nothing has happened at either of those places. this of course, jon, this is one of these days things will not again be the same in