I think that they are going to depopulate us by bringing in disease, personally. It fits the profile of using our own technology against us.
Of course, we'll respond by nuking Mecca and Medina, but it will be too late for us anyway. I just don't see any way out of this, as they are crazed lunatics bent on our destruction at any cost, as they have "God on their side".
What about that affrontive "shrine" at the Temple Mount? Shouldn't we dismantle that, too.