That new and savage act by Isis. Video that appears to show a mass execution of Christians on a beach off the mediterranean. We're not going to show you that video, but it does raise new concern tonight. Is Isis expanding their reach? ABC's chief investigative correspondent Brian Ross with the map tonight, showing how quickly that reach is growing. Reporter: The Isis propaganda video sent its message of religious hatred with an ugly glee. 21 Christian construction workers from Egypt, marched single file in Orange jumpsuits in broad daylight on a beach in Libya, and then beheaded. The leader, well-spoke in English, without a british accent. And we will conquer Rome, by Allah's permission. Reporter: The barbaric act got the immediate attention of the vet can today, and pope Francis. They were murdered just for being Christians. Reporter: And it also got the attention of the Egyptian air force, whose jet fighters attacked Isis targets in neighboring Libya. The new Isis video underscored the group's continued expansion beyond Iraq and Syria, to alliances with and allegiance from terror groups in Libya, Yemen, Pakistan and Afghanistan. Increasingly what was first seen by the U.S. As a rag tag collection of thugs, is evolving into a governing body. Its recent propaganda videos showing what it says is everyday life under its rule of terror. In fact, recent online messages say Isis "Not only needs fighters, but also needs doctors, engineers, et cetera." By making a move into Libya, Isis is that much closer to Europe, just across the mediterranean, claiming it is now on its way to Rome, a police of great symbolic importance for christianity. Just a few hundred miles away. Brian Ross, thank you.