Middle School Hostages

According to the AP, the attack was the latest blamed on secessionist Chechen rebels...

Wait a sec...aren't those secessionists Muslim? Isn't the war in Chechnya one of the forging grounds for mujahedin? And isn't there MO characteristic of Islamic holy warriors worldwide?

The AP article above does mention the involvement of a Chechen islamist group, but why do all the headlines speak of "gunmen" or "rebels," and not "Islamic terrorists?"