1) warn them that if the anthrax, hijackings, and other nonsense doesn't stop, their most precious holy site - Mecca - is literally toast
2) if it doesn't stop, drop the bomb on Medina (holy site #2) and warn them that Mecca is next
3) if it still doesn't stop, DO IT
Short of killing ALL of them (which will never happen) THAT is what will work.