(CBS News) At a NATO summit, President Barack Obama and other world leaders Monday affirmed plans to gradually withdraw foreign forces from Afghanistan, handing over security responsibility to Afghan troops next year.
The agreement comes as the relationship between U.S. and Afghan soldiers is at an all-time low. The coalition began a study of afghan attacks on U.S. allies after six American soldiers were killed during a joint patrol in 2010.
The report was finished last year, but was quickly classified. CBS News correspondent Allen Pizzey, reporting from Kabul, has some details of what it says.
The murder of U.S. troops by Afghan soldiers they train and fight with is "a growing systemic threat" according to a coalition report issued last May. Since then, the number if attacks has increased.
At least 55 American troops have been killed since July 2010. More than 75 percent of the incidents happened in the last two years.
The bloodshed threatens to fracture trust between the forces and the new Afghan army -- a key element of the plan to withdraw in 2014.
Brigadier General Karsten Jacobsen is the spokesman for coalition forces -- also known as the ISAF forces -- in Afghanistan.
"The vast majority of the cases where we have found reasons are coming from individual challenges --that is battle stress, battle fatigue, that is people who are, who are under strong emotional influences," Jacobsen said.
But the report concluded the killings were triggered by cultural misunderstandings and insults. Interviews with hundreds of U.S. and Afghan troops revealed a deep-seated contempt on both sides.
Americans complained the Afghans were undisciplined in combat, thieves and drug-users. Among the comments: "They are stoned all the time; some even while on patrol with us" and "They are pretty much gutless in combat. ... We do most of the fighting"
Afghans interviewed for the report were equally scathing, describing American troops as bullying and disrespectful. The most frequent complaints: "U.S. soldiers don't listen; they are too arrogant" and "They get upset due to their casualties, so they take it out on civilians during searches."
The worst point of friction -- night raids on homes -- has been fixed. They are now only conducted by Afghan forces.
Nonetheless, American troops in joint bases with Afghans sleep with what they call "a guardian angel," one man awake and armed.
Even at training centers, no one relaxes their guard, according to First Lieutenant Cory Scanlon.
"You can't be too critical or else they'll get upset, because there's a lot of honor at stake," Scanlon said. "So sometimes you have to be careful with how you address people."
The seriousness of that is summed up by an Afghan proverb -- "Life over wealth, honor over life" -- which goes some way to underline that what might be consider merely offensive behavior in Western culture can be mortal in Afghanistan.