(CBS/AP) WASHINGTON - Defense Secretary Leon Panetta said Tuesday he was awaiting details from Gen. John Allen, the top commander in Afghanistan, on his plan for bringing home the remaining 23,000 troops sent to Afghanistan during the 2010 surge. After the weekend's mass killing of Afghan civilians in the southern province of Kandahar, allegedly by an Army staff sergeant, Panetta and other top administration officials said it would have no effect on the war strategy. That does not mean, however, that the planned troop withdrawal won't be accelerated at some stage. Defense chief Leon Panetta says "war is hell" Clinton: U.S. Afghan strategy remains "steadfast" U.S.: Killing of Afghans won't alter war plans Panetta, speaking to reporters on a flight to Bishkek, Kyrgyzstan, said that despite recent setbacks, including the burning of Korans by U.S. soldiers last month and the massacre of 16 Afghan civilians over the weekend, allegedly by a U.S. soldier, there has been no change in plans to complete a troop withdrawal by the end of 2014. Obama vows to hold Afghan killer to account Afghan officials fired upon at site of massacre Allen said on Monday that there are about 90,000 U.S. troops in Afghanistan now. He said he plans to bring out 23,000 of those by the end of September, as required by President Barack Obama, but Panetta has yet to endorse that exact schedule. Obama has given Allen no orders on specific troop withdrawals beyond September, except to say there will be a "steady pace" of withdrawals between now and the end of 2014, when Afghan forces are to be fully in charge of the country's security. On CBS "Face the Nation" Sunday, White House correspondent Norah O'Donnell reported that the president had already spoken with Afghan President Karzai last week negotiating on a broader strategic agreement to help transition U.S. forces out of Afghanistan from a combat role to a training role. She also said there will be a NATO meeting in Chicago in May on how to pull out the forces and accelerate the transition. Also on Face the Nation, Obama's potentail GOP rival for the presidency, Newt Gingrich, called for U..S. troop withdrawal from Afghanistan following the rampage incident. He said the the U.S. doesn't have the "willpower" or the "capacity" to "fundamentally change the region." "We're not prepared to be ruthless enough to force them to change," Gingrich said on the program. However, retired Gen. Michael Hayden, the former CIA head, said on "CBS This Morning" Tuesday that the U.S. has to stay the course in Afghanistan despite the civilian shooting deaths, and believed that the present plan for withdrawing the troops is already too rapid. "We've deployed fewer forces in the surge than were originally called for," he said, "we're pulling the surge forces out earlier than we had anticipated, and now there's some talk of moving that 2014 hand-off date back towards 2013. The New York Times reported Tuesday that the administration is considering a range of options for further troop reductions after September. One option is for at least 10,000 more to come home by the end of December, and then 10,000 to 20,000 more by June 2013, the Times reported, citing unnamed administration officials. Asked about the Times report, Pentagon press secretary George Little, who is traveling with Panetta, said, "The analysis on drawdown scenarios isn't yet complete, and the secretary (Panetta) has not been presented with options. It's premature to speculate on any drawdowns beyond those associated with U.S. surge forces in Afghanistan. Earlier, Panetta said he had not yet seen details of Allen's plan for a drawdown this summer. "What I am awaiting are General Allen's plans with regards to taking down the remaining 23,000 from the surge," Panetta said. And, we'll review those plans. On Tuesday, Obama insisted that the killings will not change U.S. commitment to finishing the job in Afghanistan, but he was clearly trying to reassure Americans that he will close out the war. "Make no mistake, we have a strategy that will allow us to responsibly wind down this war," Obama said. We're steadily transitioning to the Afghans who are moving into the lead. And that's going to allow us to bring our troops home. He repeated the timetable for bringing forces home that he had already laid out: 23,000 troops by the end of this summer, on top of 10,000 removed last year. He did not give a schedule for withdrawal of the approximately 68,000 U.S. forces that will remain in Afghanistan at the end of this year. The U.S. and NATO allies agreed more than a year ago to leave forces in Afghanistan through 2014. There is political pressure in Europe, and increasingly in the United States, to speed up that deadline. "There's no question that we face a difficult challenge in Afghanistan, but I am confident that we can continue the work of meeting our objectives, protecting our country and responsibly bringing this war to a close," Obama said.