Extraordinarily keen observation by a British Royal Navy officer narrowly averted a potentially tragic friendly fire engagement using a Predator or Reaper UAV.

The UAV operator had been given clearance to engage the targets -- a group of 7-10 men -- in an operational theater. The men had been identified as hostile forces.

The navy officer, believed to be working as part of a joint US-UK UAV force operating from Creech AFB, Nevada, noticed that the men, while dressed in local attire, did not actually walk in the same manner.

This single observation led to the potential engagement being called off. The group were in fact special forces.