It's also possible this is a combat demo for one of the newer UCAVs coming down the pipe. The X47 series, the Neuron, the Mantis/Barracuda, all look very similar. Traingular with a roundish hump in the middle. Not exactly an uncommon design (flying wings have huge advantages).
The best way to get money out of governments for this stuff is to blow a bunch of shit up. And for marines standing so close to a "terrorist camp" they sure don't seem very concerned.