The u.S. Military evacuated americans out of the embassy in yemen and they are intensifying the hunt for the leaders of the terror plot. So does this mean the risk has increased tonight? Abc's chief... See More
The u.S. Military evacuated americans out of the embassy in yemen and they are intensifying the hunt for the leaders of the terror plot. So does this mean the risk has increased tonight? Abc's chief foreign affairs correspondent martha raddatz tells us what is happening right now. Reporter: Today a u.S. Navy reconnaissance plane circled yemen's capital, scouring the streets and alley ways below searching for terrorist operatives behind a plan u.S. Intelligence believes involves a strike on the u.S. Embassy or other western targets with explosive trucks. Craig, a freelance journalist in the city described the eyes in the sky. It was buzzes for about an hour and then it was back again. Reporter: Taking no chances, the u.S. Air force air lifted am all of the u.S. Personnel out to safety, leaving only the most essential personnel behind. Tonight we know this is the man behind the plot, a hardened al qaeda leader determined to strike beyond the borders of yemen to the american homeland. He was behind the underwear bombing plot to bring down a u.S. Aircraft. He just might get help from a large number of maximum security prisoners, many of them al qaeda, who have been busted out of jail in recent weeks with the help of heavily armed militants. 500 were freed in iraq, more than 1,000 from a prison in libya and close to 250 from a pakistani jail. Many could again link up with al qaeda. It's possible they could be suicide bombers or combat anti-s. Some may have capabilities in terms of bottom making which is always a concern. Reporter: These embassies will remain closed through the weekend but concern about the possibility of an attack before that is very real. Diane and very urgent. Continues to be on high alert. Martha, the other headline in the news today, 11 months after the attack on the consulate of ben ganzy, we know they have brought charges against one accused attacker. What do we know about him. The charges are sealed. He's one of those self-formed militia leaders. He says he is not al qaeda but witnesses say he was organized that night in benghazi. He says he was there but did not cause violence. This is an arrogant guy who was hanging out at luxury hotels but right now he is in hiding. And here at home today surprising news about the health of former president george w.
This transcript has been automatically generated and may not be 100% accurate.