The photos have limited focus and resolution, but the pests appear to have segmented bodies with 2 pairs of legs per segment. That makes them millipedes. However, millipedes usually eat dead and decaying plant material. The affected pomegranate branches appear to be heavily damaged, and I suspect the millipedes are taking advantage of the damage and resulting decay.  I don't think they're the cause of your problem.  I suggest pruning out the damaged branches. Burn or trash them.
Rick Coke