There's only one way to stop this. You Kill them all, Break all their stuff, and burn every single thing they own. You take nothing from the field and leave not a single stone stacked upon another or blade of grass un-scorched. It needs to be violent and unforgiving. You make it so horribly disturbing to witness that no one will dare choose to be a terrorist ever again.
This needs doing and Right the F*** Now is Not Soon Enough. Not because we fear or hate them, but because they would not leave us alone.