Updated

U.S. counterterrorism officials have set their sights on the top bomb maker of Al Qaeda's Yemeni branch, who the officials identified as a central figure in at least three new potential terror threats involving Americans or American targets.

Ibrahim Hassan Tali al Asiri, the bomb maker, poses a lower-profile but more lethal threat to the U.S. than the group's prominent propagandist Anwar al-Awlaki, who the CIA killed last month, U.S. and international counterterrorism officials said.

Asiri is one of the top al Qaeda operatives in the crosshairs of the CIA's new drone program in Yemen, which the agency inaugurated with the Sept. 30 strike on Anwar al- Awlaki, who was the charismatic, American-born face of Al Qaeda's Yemen branch, officials said.

With Awlaki dead, U.S. counterterrorism officials turned their attention to other imminent threats such as Asiri and Nasir al Wahishi, Usama bin Laden's former secretary in Afghanistan, who now heads Al Qaeda's Yemen branch.

Asiri has been involved in all of the group's major plots in the past two years, U.S. officials claim, including an August 2009 attempt to kill a Saudi prince, the botched 2009 Christmas Day airliner bombing and a foiled 2010 cargo plane plot.

U.S. officials investigating Asiri say he has been scouting out U.S. airline and other domestic targets on the internet, researching the security measures taken and devising ways to circumvent them.

To read more on this story, see The Wall St. Journal article here.