The IS jihadists are a threat to the world as they vow to conquer the US.
The IS militants have already pledged attacks on the United States, proclaiming that their flag will fly over the White House. Despite US air strikes and international outcry they show no signs of stopping either. If they are in some way defeated in Iraq and Syria, the surviving IS militants will disperse to other parts of the world and conduct terror attacks wherever they can, including in the United States.
The Islamic State terrorists are definitely a horrifying threat to the world.