It's highly unlikely that al-Qaida's top leader, Ayman al-Zawahri, or his chief lieutenant in Yemen, Nasser al-Wahishi, were personally part of the Internet chatter or, given the intense manhunt for both by US spy agencies, that they ever go online or pick up the phone to discuss terror plots, experts say.
But the unspecified call to arms by the al-Qaeda leaders, using a multi-layered subterfuge to pass messages from couriers to tech-savvy underlings to attackers, provoked a quick reaction by the US to protect Americans in far-flung corners of the world where the terror network is evolving into regional hubs.
A US intelligence official said the unspecified threat was discussed in an online forum joined by so many jihadist groups that it included a representative from Boko Haram, the Nigerian insurgency that has loose and informal ties to al-Qaeda. Two other intelligence officials characterised the threat as more of an alert to get ready to launch potential attacks than a discussion of specific targets.
All three intelligence officials spoke on condition of anonymity because they were not authorised to discuss the threat.
Rita Katz, director of the Washington-based SITE Intelligence Group that monitors jihadist websites, said it's all but certain that neither al-Zawahri nor al-Wahishi would communicate directly online or on the phone.