ISAF spokesman Brig. Gen. Gunter Katz told CBS News the latest attack is, “tragic, but doesn’t reflect the security situation.” He calls the shooting an “isolated incident”. “We’re confident this won’t stop operations,” he said. “We trust our Afghan partners. But we’re looking at how to mitigate incidents.” White House press secretary Jay Carney said he didn’t want to “diminish at all the seriousness of the attack” but “it is important within the context here to recognize that missions … are being conducted ever day, every hour involving U.S. forces and the 330,000 Afghan forces.” He added that the U.S. military “believes that the operational impact [of the attacks] has been negligible.” The Afghan security forces have established an eight-point vetting process. Katz explained that recruits require two letters from local elders as a character reference as well as biometric, medical and drugs checks, but ISAF is still working with the Afghan forces to improve this process. Nonetheless, early in 2012, top U.S. commander Gen. John Allen ordered American units to select a “guardian angel” to watch over fellow troops, even as they sleep, at joint U.S.-Afghan bases and on joint operations involving live fire – a direct response to the mounting green-on-blue attacks. Last year, a U.S. Army team led by a behavioral scientist produced a 70-page survey that revealed both Afghan and American soldiers hold disturbingly negative perceptions of the other. According to the survey, many Afghan security personnel found U.S. troops “extremely arrogant, bullying and unwilling to listen to their advice” and sometimes lacking concern about Afghans’ safety in combat. They accused the Americans of ignoring female privacy and using denigrating names for Afghans. American troops, in turn, often accused Afghan troops and police of “pervasive illicit drug use, massive thievery, personal instability, dishonesty, no integrity,” the survey said. U.S. military officials have downplayed that survey. The U.S. hopes the Afghan Local Police, a village defense force backed by the national government, will become a key force in fighting the insurgency.