Provide buses. Lottsa and lottsa buses. Failing that Beer. Lotsa and lotsa beer. Oh yeah, find out where your local mosques are so we can destroy them in the event of an attack.
Beer.... a good PBR can be a Godsend.
But really, the only way is the way the German army dealt with partisans. When you catch one, kill him on the spot. It is in the geneva conventions that person out of uniform may be dealt with in this manner.
Not very P.C, but effective.