on the local paper. Aditi roy. Americans suddenly evacuated overnight from yemen on air force planes as the terror alert there reaches its highest level. Abc's martha raddatz has the very latest, now,... See More
on the local paper. Aditi roy. Americans suddenly evacuated overnight from yemen on air force planes as the terror alert there reaches its highest level. Abc's martha raddatz has the very latest, now, from washington. Martha, good morning to you. Reporter: Good morning, josh. This was a dramatic overnight operation, under high security. Almost all u.S. Personnel loaded on to an air force c-17 to fly them to safety. The ambassador himself is already in washington and will not likely be returning anytime soon. This plot leads to the highest levels of al qaeda and the man who was once bin laden's closest associate. A u.S. Official tells abc news it was ayman al zawahiri, who directed al wuhayshi, to carry out an attack. U.S. Intelligence intercepted the communication between the two men, which prompted the closure of embassies in the middle east, africa and south asia. This group is fairly ingenious, fairly bold and eager to cause challenge. Reporter: The initial target is believed to be the u.S. Embassy in yemen. This is why the state department has ordered the evacuation of all nonemergency personnel from yemen because of the threat. Intelligence officials believe trucks have been packed with explosives to carry out the attack in yemen. And a frantic search is under way. The u.S. Has intercepted communications between al qaeda affiliates and someone in the united states, including communications through the mail, although, the contents is not known. The simpler, more perimeter form of communication, the more effective they are. Reporter: Overnight, there was a drone strike reported in yemen. The fourth this past week. This threat is ongoing. Thank you very much.
This transcript has been automatically generated and may not be 100% accurate.