You're right, though: having this unregulated, invisible army can pose a serious security risk to U.S. forces.

No longer are religious conservatives here described as "the invisible army."

Throughout the small town the invisible army found other victims and murder reigned triumphant over every living thing.

"You're looking for an invisible army, one that evaporates and blends in with the population," he added.

An invisible army of suffering people and one day we shall become them.

There is no invisible army of blood-sucking ghosts, do you understand?

His huge number of devoted loyalists, particularly in Iowa, were called "the invisible army."

And at the same time Bolan realised he, too, was being seen and studied by the eyes of an invisible army.

Four years ago, many people believed that Pat Robertson had an "invisible army" of Christian fundamentalists to aid his campaign.

Her question was so simple, yet it implied the obvious: The Mafia is an invisible army with plenty of soldiers.