JIDDAH, Saudi Arabia (AP) — Key Arab allies promised Thursday to “do their share” to fight Islamic State militants, but NATO member Turkey refused to join in, signaling the struggle the U.S. faces in trying to get front-line nations to put aside their regional animosities and work together to defeat a common enemy.

The Arab states’ endorsement of a broad strategy to stop the flow of fighters and funding to the insurgents, and possibly to join military action, came as the CIA doubled its assessment of how many fighters the extremist group can muster.