Surround them and keep up the noise. If they bring in horses. Form a wall of people point back the way they arrived. Horses don't like humans. Horses, even trained horses will not advance against a wall of people and if those people are pointing for them to leave - Horses Will Leave.
The answer to the idea of being at war with non-believers, is Christ. God is opening the minds of the Uma, especially via dreams but also via the Internet.