"Therefore, effective immediately, Defense Department personnel are prohibited from using geolocation features and functionality on government- and non-government-issued devices, applications, and services while in locations designated as operational areas", according to the memo.
Specifically, their use can be authorized after "conducting a threat-based comprehensive Operations Security (OPSEC) survey" or if the use of geolocation on government-issued devices is necessary to carry out a mission.
The Pentagon discovered a fitness tracking app may have accidentally revealed security force locations around the world.
Shanahan said in the memo, dated August 3 and released Monday, that the rapidly evolving market of devices, applications and services using geolocation "presents significant risk" to USA troops and Defense Department employees.
The memo, obtained by The Associated Press, stops short of banning the fitness trackers or other electronic devices, which are often linked to cellphone applications or smart watches and can provide the users' Global Positioning System and exercise details to social media. The map showed bright spots of activity in places such as Syria and Somalia, where there were otherwise few users of fitness trackers.
"We don't want to give the enemy any unfair advantage", Army Col. Rob Manning, a Pentagon spokesperson, told reporters on Monday.More news: Snapped! Alligator makes for a graduation photo with a difference
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A portion of the Strava Labs heat map from Kandahar Airfield in Afghanistan, made by tracking activities.
Manning said the department will continue to study the risk associated with these devices and change the policy as needed.
"Zooming in on one of the larger bases clearly reveals its internal layout, as mapped out by the tracked jogging routes of numerous soldiers", The Guardian reported at the time. In May, defence officials laid out new restrictions for the use of cellphones and other mobile wireless devices inside the Pentagon.
This includes fitness trackers, smartphones and potentially even dating apps.
That memo called for stricter adherence to long-held practices that require phones be left in storage containers outside secure areas where sensitive matters are discussed.
Operational areas are places where "military personnel are there for a very specific goal or mission" such as Operation Inherent Resolve or Operation Freedom's Sentinel, according to Maj.