In the course of one week, the burning of copies of the Koran by U.S. military personnel in Afghanistan has set off a deadly chain of events that has not only inflamed tensions but possibly exposed a crippling weakness in the American strategy to wind down the war. 
 
 The emerging U.S. strategy in Afghanistan is built around plans to replace large NATO combat formations with small teams of advisers who will live and work alongside their Afghan partners. 
 
 But the killing of two high-ranking NATO officers by an Afghan security official — and the subsequent decision by the top NATO commander in the country to recall his personnel from top Afghan ministries — has spurred doubts about whether Afghan security forces can be relied upon to provide for the protection of their Western partners. The consequences of that erosion of confidence, former U.S. officials and analysts say, could be devastating. 
 
 “If the trust, ability and willingness to partner falls apart, you are looking at the endgame here,” said Mark Jacobson, who served until last summer as the NATO deputy senior civilian representative in Kabul. 
 
 The killing of the U.S. officers on Saturday occurred two days after a man wearing an Afghan army uniform fatally shot two American troops in eastern Afghanistan, the latest in a string of incidents in recent months in which local security forces have turned against NATO personnel. 
 
 Some of the killings have been perpetrated by Afghan troops whose loyalties lay with the Taliban. But, in most cases, the attacks have been the result of tensions between U.S. forces and Afghans who felt as though they had suffered an insult to themselves or their faith. 
 
 On Sunday, Afghan President Hamid Karzai, who initially responded to the Koran burnings with outrage, sought to stem the latest wave of violence by issuing a plea for calm and blessing the withdrawal of NATO advisers from his ministries as a justifiable measure. 
 
 But protests continued, including in the northern city of Kunduz, where Afghan demonstrators opened fire and tossed a grenade at a U.S. base, wounding seven American troops. The Afghan defense and interior ministers canceled a long-planned trip to Washington to focus on curbing the violence, which has claimed 25 Afghan lives. 
 
 “We remain committed to a partnership with the Afghan government and people,” the U.S. ambassador to Kabul, Ryan C. Crocker, told CNN on Sunday, promising that American service members and civilians would continue to work with their Afghan allies. 
 
 For now, though, much of the cooperation between U.S. advisers and their Afghan partners is on hold. And even though the decision to withdraw the advisers is probably temporary, it is not clear how U.S. troops will be able to reestablish trust with Afghan security forces. 
 
 “This is not going back to business as usual,” an Army officer who works as an adviser in Kabul said Sunday. “The threat is still higher than normal.” 
 
 Once advisers return to the ministries, the officer said, some will probably have to shorten their visits, instead of remaining there for six- to 10-hour shifts, to reduce risks. 
 
 Senior Obama administration officials have sought to reassure a war-weary American public that the NATO combat mission in Afghanistan would draw to a close by the middle of next year. These officials have implied that the change to an advisory mission would not only mean fewer U.S. service members in Afghanistan, but also less risk for the noncombat troops who remain behind. 
 
 Military experts, however, say that the smaller U.S. advisory force might be more exposed to fratricidal attacks than conventional military units. Such attacks — which were exceptionally rare in Iraq — often stem from a cultural chasm between U.S. and Afghan troops. 
 
 Carter Malkasian, who served as a State Department adviser in southern Afghanistan’s Helmand province in 2010 and 2011, said one way to mitigate that risk is for advisers to build closer relationships with their Afghan partners. But the risk will always be there. 
 
 “The most effective advisers will be with their Afghans all the time, and that certainly does involve additional risk,” Malkasian said. 
 
 Unlike a typical infantry platoon, which consists of more than 35 heavily armed soldiers, the advisers work in teams of as few as a dozen troops. Some military and civilian advisers working in Afghanistan said Sunday that the risks associated with their jobs were still manageable and that they believed that they would soon be able to return to their work. 
 
 “I hope [the ban] is lifted soon,” said a State Department adviser working at a remote outpost in eastern Afghanistan. “Maybe I am complacent. I know we face all kinds of threats, but we have a job to do.” 
 
 Current plans call for the U.S. force in Afghanistan to fall from a peak of 100,000 troops to about 68,000 by the end of the summer. Further reductions are likely later this year and in 2013. All NATO combat troops are expected to be withdrawn by the end of 2014. 
 
 In an article in the upcoming issue of Foreign Affairs, Malkasian and Kael Weston, who served a multiyear stint as an adviser in southern Afghanistan, estimated that NATO could hold off the Taliban and keep the Afghan government and security forces functioning with as few as 25,000 advisory troops. 
 
 The Afghans would rely on the NATO advisers to call in airstrikes if their position was about to be overrun by a larger Taliban force. The advisers would ensure that their Afghan partner units were receiving ammunition, food and fuel from their headquarters. The Westerners also would help control the most damaging and overt acts of corruption. 
 
 To be effective, these troops would have to live without large American bases, expensive dining facilities and intensive quick-reaction forces. 
 
 “The more willing advisers are to accept risk,” Malkasian said, “the more effective they will be.” 
 
 Special correspondent Javed Hamdard in Kabul contributed to this report. ||||| Afghan protesters shout anti-U.S. slogans during a protest in Kunduz province. Four people were shot dead by Afghan security forces on Saturday as protests over the burnings of the Muslim holy book at a NATO base erupted for a fifth day, with an attempt by demonstrators to bombard a U.N. compound in the north. (Reuters) 
 
 The top U.S. commander in Afghanistan on Saturday recalled all NATO personnel working in Afghan ministries in the Kabul area — a bold and potentially divisive response to the killing of two American service members by an Afghan security official in the country’s fortified Interior Ministry earlier in the day. 
 
 Marine Gen. John R. Allen’s directive comes five days after U.S. military personnel burned a pile of Korans at the largest military base in Afghanistan in an apparently inadvertent act that set off violent protests across the country. More than 25 Afghans have died in those demonstrations, and four NATO soldiers have been killed by men wearing Afghan security uniforms since Thursday, when the Taliban urged Afghan soldiers and police to turn their weapons on their Western counterparts. 
 
 The week’s events have exposed a core vulnerability of the Obama administration’s strategy for winding down the decade-long Afghan war: a fraying trust between two presumed allies who must depend on each other to keep the insurgency at bay. 
 
 Although mutual suspicions have been building for some time, the Koran burnings followed by the apparent revenge killings of U.S. military personnel will make it much harder for both sides to agree in the coming weeks on the specific terms and timetable of NATO’s planned withdrawal from Afghanistan by the end of 2014. 
 
 NATO leaders are scheduled to hold a summit in May in Chicago, where they had hoped to finalize details of the withdrawal and the gradual handover of security responsibilities to Afghan forces, as well as report progress in fledgling negotiations with the Taliban. 
 
 But inflamed public anger among all sides could force a reassessment of those plans. Afghan patience is wearing thin with repeated acts of cultural insensitivity by foreign troops. Meanwhile, Americans and Europeans are growing increasingly resentful of the mounting number of treacherous attacks by Afghan forces they are trying to train. 
 
 The escalating tension here prompted apologies for the Koran burning from President Obama and several top U.S. defense officials. But demonstrations continued unabated Saturday, even before U.S. officials reported that an Afghan security officer had killed an American colonel and major in one of Kabul’s most important and most impenetrable ministries. 
 
 The two men, whose names have not been released, were shot in the back of the head while working at their desks. 
 
 Within hours of the attack, Allen recalled Western advisers from Afghan ministries, citing “obvious force protection reasons.” The decision will affect several hundred officials who work with the Afghan military and with a host of other government agencies, such as the education and agriculture ministries. 
 
 Fratricide has been a growing problem between Afghan soldiers and their foreign counterparts here. In the past, Western military advisers were told to operate cautiously after such incidents, but Allen’s decision represents the first time a commander has publicly withdrawn personnel from their posts for fear of attacks by men in Afghan uniforms. 
 
 The Taliban promptly asserted responsibility for Saturday’s attack, saying the shooter was an insurgent who had infiltrated the Afghan security forces. 
 
 Western military advisers were warned of a heightened risk of fratricide this week and told to stay out of Afghan ministries unless their activities were “mission critical.” 
 
 Although Allen’s announcement will have the most direct impact on those managing Afghan military policy from Kabul, the relationship between Afghan and American soldiers who live and fight alongside one another far from the capital has also turned icy this week. On shared bases in eastern Afghanistan, U.S. military commanders ordered their soldiers to keep their distance from the Afghan counterparts until tension dissipated. 
 
 “The mission requires us to spend time with our Afghan counterparts, and lately we haven’t been able to do that,” said one military official in the east who spoke on the condition of anonymity. 
 
 NATO forces will continue to withdraw troops from Afghanistan through 2014, and the United States is expected to rely increasingly on small teams of advisers who will assist Afghan soldiers as they assume control of the country’s most volatile provinces. But if the military partnership continues to sour, some wonder whether those advisers will be able to operate safely and effectively without the support of a vast Western security apparatus. 
 
 Violent protests began outside Bagram air base early Tuesday after the incineration of Muslim holy books was discovered by Afghan employees. Those demonstrations have rattled the already fragile alliance between NATO forces and the people and government of Afghanistan. Afghan lawmakers have asked that the culprits be tried in an Islamic court. 
 
 Allen said in a statement that the investigation into the Koran burning is ongoing. “Working together with the Afghan leadership is the only way for us to correct this major error and ensure that it never happens again,” he said. 
 
 He has apologized profusely for the incident, which some officials said involved Korans confiscated from a prison near the Bagram base because they were suspected of being used to pass inflammatory messages. 
 
 In addition to Allen’s statements and Obama’s apology to Afghan President Hamid Karzai, the U.S. military has pledged new training to avoid similar mistakes. But the outreach has done little to quell the anger surging through Afghanistan and other parts of the world over an act that Muslims consider a desecration. 
 
 U.S. officials say they are disappointed that Karzai has not more vehemently demanded an end to anti-American protests and accepted the U.S. apologies. Karzai issued a statement urging Afghans “not to resort to violence” earlier in the week, but he has since struggled to balance domestic calls for retribution with American calls for reconciliation, declining to publicly offer Americans the kind of absolution that some officials think might put an end to the violence. 
 
 Afghan Defense Minister Abdul Rahim Wardak called Defense Secretary Leon Panetta on Saturday to apologize for the killings of the two U.S. military officials and offer his condolences, Pentagon press secretary George Little said. Wardak added that Karzai was assembling a group of religious leaders, lawmakers and other officials to take urgent steps to protect NATO forces and curtail violence in the country. 
 
 Wardak and Interior Minister Bismillah Khan Mohammadi are scheduled to visit Washington on Thursday to meet with Panetta and other Pentagon officials. 
 
 For his part, Karzai seems keen on using the Koran-burning incident to press his case that Afghans should take responsibility for the U.S. detention facility at Bagram. 
 
 “The sooner you do the transfer of the prison, the less you will have problems and unfortunate incidents,” Karzai said at a meeting with Deputy Defense Secretary Ashton B. Carter on Wednesday. 
 
 At least three people were killed and dozens wounded Saturday when protests turned violent in Kunduz, a province in northern Afghanistan. One crowd tried to storm the U.N. compound there but was turned back by armed guards. 
 
 “Although caused by legitimate defense, the United Nations . . . regrets the casualties among the demonstrators and expresses condolences to the families of those who lost their lives,” the U.N. Assistance Mission said in a written statement. 
 
 Staff writers Rajiv Chandrasekaran, Greg Jaffe, Craig Whitlock and Scott Wilson in Washington contributed to this report.
– Afghanistan has roiled with violence for the past week over the Koran burnings at Bagram, leading to questions of whether the American exit strategy will actually work as planned. The US, Britain, Germany, and France temporarily removed hundreds of advisers from Afghanistan over the weekend in the wake of several retaliatory attacks—four US troops have been killed by Afghan comrades since the protests began—and some fear that Afghan security forces will not be able to protect the few Western advisers who will remain in Afghanistan after the withdrawal is complete. One adviser says he expects that upon their reinstatement, shifts will have to be shortened for the advisers' protection. Recent months have seen a number of incidents involving Afghan security forces turning on NATO personnel—and only some out of those incidents arose out of loyalty to the Taliban, the Washington Post notes. Most involved Afghan troops who felt insulted in some fashion, such as after the Koran burning came to light, and military experts think there could be an even higher risk of such attacks after the military withdrawal. A former US Army Ranger tells the Wall Street Journal that Americans are wary of sending advisers "to a country where those trainers and advisers are liable to be targeted by the very people they are training and advising."