(CBS News) KANDAHAR, Afghanistan - The recent wave of Afghan soldiers killing their NATO partners has led to a stark new reality for troops serving on the front lines.
Lt. Colonel Leroy Barker commands a small combat outpost in Kandahar Province, Afghanistan. About two weeks ago, he received orders to reinforce his position, but not against the Taliban. Lt. Colonel Barker's orders were to reinforce his position against possible attack from his Afghan partners.
While, there has not been a so-called "green on blue" killing at the outpost, the new directive has already driven a wedge between U.S. and Afghan forces.
The American and Afghan troops are currently separated by a cement walkway. A U.S. soldier armed with a machine gun keeps a watchful eye on his Afghan partners 24 hours a day. U.S. troops call their section of the outpost the Alamo.
"They're always looking out for it. It's always in the back of their mind," says Lt. Colonel Barker. "[It's] kind of like working with a tiger. You never want to turn your back on it, no matter how much you trust it."
Photos of the base's top two Afghan commanders are pinned to a wall inside the guard post. They are the only Afghans allowed into the American side of the base. Unidentified Afghans who turn up may be shot.
The base is located along the edge of a major route used by the Taliban. A blimp, equipped with a camera, flies above the base looking miles away for any suspicious activity. Identifying a threat on the other side of the base though is a much more difficult proposition.
Afghan security forces were recruited so quickly that little is known about them. Under the new orders, every Afghan is now fingerprinted and has their eyes scanned. That information is then registered in a database.
Lt. Colonel Barker's men are eager to return to "Taliban country". Their movements have been restricted by the new orders.
At a checkpoint once manned by American personnel, a disorganized group of Afghan soldiers stand guard. They have few uniforms, but plenty of guns.
While this scenario presents a potential danger, Lt. Colonel Barker sums it up by simply: "We've got to try and continue with this relationship as best we can."