TODAY | August 05, 2013
>> clearly the u.s. officials are taking these threats very seriously. this morning we're learning more about where they're coming from.
>> let's get right to richard engle in cairo for us this morning. richard , good morning to you.
>> reporter: good morning, savannah. the u.s. embassy behind me is closed today like so many embassies in this part of the world because of this terror threat which is described as specific enough to be credible yet too vague to know exactly where an attack might take place. the u.s. has extended the closures of 15 diplomatic posts and added four more. all to remain shut, at least until the weekend. until the muslim holy month of ramadan is over.
>> the announcement itself may also be designed to interrupt al qaeda planning to put them off stride and put them off the bat po foot and let them know we're on to a portion of the plot line.
>> reporter: al qaeda militants have been discussing what a senior u.s. officials described as a single significant event or a series of simultaneous attacks. most likely in the middle east . no specific threat to the united states but officials couldn't rule one out either. president obama gathered his national security team. congressional leaders given classified briefings.
>> there's been a lot of chatter out there. chatter means conversation among terrorists about the planning that's going on. very reminiscent of what we saw pre-9/11.
>> this specific threat has reached a new level.
>> reporter: senior intelligence officials say the plot originates with yemen with al qaeda in the arabian peninsula , the same group that mailed explosives in a printer to chicago. they have a uniquely skilled bomb maker and is seek revenge after it's commander was killed last month in a drone strike. the group's leader was once bin laden 's secretary and is well connected to al qaeda 's top leadership.
>> in many ways it's more dangerous. now we have 2.0 or 3.0 which is widely dispersed a younger generation coming up with new ideas. not necessarily repeating what they did in the past.
>> reporter: among those new ideas and new tactics, savannah, we are told that al qaeda militants in yemen has been experimenting with surgically implanting explosives inside a bomber's body to try and avoid airport security .
>>> richard engle with the latest