US ties with Afghans face crisis after violence Deadly unrest in Afghanistan has thrown a spotlight on the uneasy partnership between NATO and Afghan forces, exposing a potential Achilles heel for a war effort that depends on building trust with Kabul's soldiers and police. The White House and the Pentagon insisted Monday that attacks on US troops, including the killing of two military advisers over the weekend, were "isolated" incidents and predicted turmoil over the burning of the Koran at an American base would soon blow over. But US commanders are increasingly concerned about a rising trend of "fratricide" in the past two years, with Afghan troops turning their weapons on their American and NATO counterparts, often out of resentment and not due to an insurgent plot. The violence that has erupted over the past week after US troops sent copies of the Koran to an incinerator at the Bagram Air Base seemed to underline a vast cultural gap between NATO troops and their purported Afghan allies, contradicting a more upbeat picture painted by the Pentagon. A recent report commissioned by the US military found deep distrust and suspicion between Afghan and US troops, even as NATO presses ahead with plans to build up the Kabul government's army and police to allow coalition forces to leave. Such fratricide-murder incidents are no longer isolated; they reflect a growing systemic threat. They are provoking a crisis of confidence and trust among Westerners training and work with ANSFs (Afghan National Security Forces)," said the 2011 report. Between November 2010 and May 2011, 16 percent of all those killed in "hostile" incidents with the NATO-led contingent were a result of "fratricidal" assaults, according to the report. In surveys of Afghan and American troops, the Pentagon report found Afghan soldiers saw their US comrades as rude, disrespectful and reckless with their gunfire when civilians were nearby. The American troops for their part described the Afghan soldiers as traitorous, lazy, drug-addled and corrupt. The brazen shooting of two US advisers inside the Afghan interior ministry on Saturday and the killing of two US troops by an Afghan soldier jolted the American military, which has put a top priority on working "shoulder to shoulder" with Afghans. "We do need to put a lid on this," said Michael O'Hanlon, a senior fellow at the Brookings Institution think tank. But he said there was still solid cooperation with the Afghan forces and that polling data showed Afghans were much more supportive of the American and NATO presence compared to Iraq, where many had viewed the US military role with contempt. It's a question not so much of whether the population has become so angry with that we can't be there. It's much more a question of whether we can deal with the infiltration and the defection dilemma," O'Hanlon said. The cases of the insider killers are obviously the huge problem. The NATO-led mission has tended to portray the "blue-on-green" turncoat attacks as the result of plots by the Taliban, or a mentally unstable personality. The shooting of the two US officers at the interior ministry prompted NATO and several European countries to pull their advisors out of Afghan government offices, and top commander General John Allen has yet to announce when the coalition officers will return to their posts. Some Republican critics of President Barack Obama said the turmoil showed the need to slow the pace of the US drawdown, while opponents of the war saw it as more evidence of a doomed endeavour. But most analysts and former officials said the latest crisis for the NATO mission likely would not trigger any radical change in approach, despite raising difficult questions. The Obama administration vowed there would no change in its strategy in Afghanistan or its timetable for a gradual withdrawal of troops through 2014. "Clearly, everybody's going to be a little more vigilant right now," military spokesman Captain John Kirby told reporters via video link from Kabul. That's the right thing to do, it's appropriate to do. But the mission itself continues.