"Coming after a period of deepening public outrage, spurred by the Koran burning by American personnel last month and an earlier video showing American Marines urinating on dead militants, the possibility of a violent reaction to the killings added to a sense of siege here among Western personnel. Officials described growing concern over a cascade of missteps and offenses that has cast doubt on the ability of NATO personnel to carry out their mission and has left troops and trainers increasingly vulnerable to violence by Afghans seeking revenge."