Defense chief Leon Panetta says "war is hell" U.S. Defense Secretary Leon Panetta, left, arrives in Bishkek, Kyrgyzstan Credit: Scott Olson (CBS News) ABOARD A U.S. MILITARY AIRCRAFT -- Flying across the Atlantic Ocean Monday evening, Secretary of Defense Leon Panetta slowly walked into the press compartment of his reconfigured 747 - known as the "doomsday plane" - looking as though he were shouldering the weight of the world. "War is hell," he grimly intoned. He was flying to meetings in Kyrgyzstan, but his thoughts were elsewhere, absorbed by the latest horror in Afghanistan - the shooting deaths of 16 innocent Afghan civilians, mostly children, allegedly by a rogue U.S. soldier. Panetta said he was "deeply shocked and saddened" by the incident - the same words other officials have used. But coming from Panetta, a man who's known for wearing his emotions on the surface, they didn't sound like talking points -- they sounded like the heartfelt words of a man who takes this kind of unspeakable tragedy personally. But when asked if this incident, along with the recent burning of Korans by U.S. troops and the violent reaction by Afghans, could lead to a reassessment of the war plan in Afghanistan, Panetta shifted effortlessly into mission mode. He said this "wasn't the first and won't be the last" of this kind of horrible event, adding "I do not believe there is any reason to change our strategy at this time." Policymakers need to keep their eyes on the purpose of the mission in Afghanistan, which he described as defeating and disrupting Al Qaeda so that Afghanistan can never again become a safe haven for terrorists bent on attacking America, he said. Reporters pressed different versions of the question: whether this is a potential turning point, or a time to reassess or accelerate the withdrawal. We were looking for wiggle room, but found none. The mission must go on, Panetta repeated. There's a drawdown schedule already in place, he said, and there's no reason to change it. 23,000 of the current 91,000 troops will be out by September. The drawdown will be complete by the end of 2014. Violence is down this year 24 percent. Again and again, he refused to budge from the current battle plan, which he insisted is working. President Obama said Monday the United States should not stay in Afghanistan any longer than is absolutely necessary -- but added that he does not want to "rush for the exits" in the wake of the shooting rampage. "It's important for us to make sure that we get out in responsible way, so that we don't end up having to go back in...but what we don't want to do is to do it in a way that is just a rush for the exits," Mr. Obama said in an interview with Pittsburgh CBS affiliate KDKA. When Panetta, wearing beat up blue jeans, got up to leave the informal press conference, he joked about the cramped press quarters, and let out a small hint of the famous Panetta laugh. But it was gone in a flash, and he took his somber mood back to his cabin in the front of the plane. There's little doubt Panetta is taking the shooting rampage very hard. But for anyone wondering if it might have lessened his determination to see the mission through - the answer, at least for now, is a firm and clear no.