A group calling itself Islamic State’s Tripoli Province claimed responsibility for an attack on Tuesday on a hotel that killed nine people, including an American. It was the first time the group came to prominence in Libya, raising concerns that the reach of the extremists is spreading beyond Syria and Iraq.

But the attacks also underlined the threat Islamic State poses to more entrenched Islamist groups such as Libya Dawn, a more moderate Islamist militia that is ideologically close to Egypt’s Muslim Brotherhood and now fights secular insurgents in eastern Libya.

Oil-rich Libya has gradually slipped into chaos since rebels toppled strongman Moammar Gadhafi three years ago, with two rival governments now claiming to run the country and myriad competing local militias effectively in control on the ground.
In an example of the anarchy creeping into the country, the head of planning at the National Oil Co., Samir Kamal, was kidnapped two weeks ago before being released Sunday. The identity and motives of his kidnappers remain unknown.

The threat to Libya represented by Islamic State is on an altogether different scale.