U.S. officials are worried that Al Qaeda has a new liquid explosive technique that can't be detected by current security measures, according to the latest trickle of U.S. official-sourced stories in the wake of the unprecedented embassy closures across the Middle East this week.
The story, up at ABC, adds some details to the general sense of why U.S. intelligence was so worried about the latest threat, and the significance of the threat's reported origin in Yemen: that's where Ibrahim al-Asiri is based, a.k.a. the guy behind the bombs constructed for the "underwear bomber" plot of 2009, along with an attempt on a Saudi intelligence chief's life using a bomb surgically implanted into the assassin. ABC explains that the newest idea, believed to be from al-Asiri, "allows terrorists to dip ordinary clothing into the liquid to make the clothes themselves into explosives once dry." Officials are also worried about a repeat attempt with a surgically-implanted bomb.
Meanwhile, the press is learning more details on the previously-reported intercepted message that led U.S. officials to the plot, which is reportedly in its final stages. While we already knew that Al Qaeda chief Ayman al-Zawahri had threatened revenge on the U.S. for a series of drone strikes in the country, a New York Times piece today discloses that the messages intercepted by the U.S. were between al-Zawahri, along with Arabian Peninsula head Nasser al-Wuhayshi (now believed to be the number 2 of the whole organization).
Even as more details emerge, the overall picture remains murky. In a press briefing today, White House spokesman Jay Carney sort of denied that the threat could reach domestically, while reiterating that U.S. intelligence doesn't really know at this point where the planned attack was targeting, only that it was "serious." From their embassy closures, one would have already guessed that officials narrowed down that threat to American government properties in the Middle East.