(CBS News) -- 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 a shooting rampage by a U.S. soldier who allegedly killed 16 Afghan civilians, including nine children.
"I think it's important for us just to make sure that we are not ... in Afghanistan longer than we need to be," Mr. Obama said in an interview with Denver CBS stationKCNC television.
In a separate interview with Pittsburgh CBS stationKDKA, Mr Obama said, "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's comments come as U.S. officials continue to investigate what happened over the weekend in Afghanistan.in nearby villagers as they were sleeping.
The administration and its allies say the shooting will not change the timetable for the United States and its NATO allies to hand over security control to the Afghans by the end of 2014.
The United States is expected to reduce its troop force to about 68,000 by the end of September from about 91,000 in Afghanistan now.
The attack comes on the heels of another incident that caused increased hostility toward the U.S. presence in Afghanistan -- the burning of Muslim holy books last month. That incident led to a week of riots and attacks that left 30 people dead, including six U.S. soldiers.
"Obviously what happened this weekend is absolutely heartbreaking and tragic, and I expressed directly to [Afghan] President [Hamid] Karzai how the American people feel any time innocent civilians, especially children .. are killed and for it to happen in this kind of terrible way I think we all are concerned about," Mr. Obama told KDKA.
The president stressed that removing tens of thousands of U.S. forces is logistically complicated and needs to be done "in a responsible way," using the Iraq withdrawal as model. Doing so, he said, will allow the Afghans to "protect their borders and prevent al Qaeda from coming back."
Asked if that meant he did not want to speed up the withdrawal, Mr. Obama said he is "more determined" to make sure the troops come home.
"It's been a decade, and you know, frankly, now that we've gotten [Osama] bin Laden, now that we've weakened al Qaeda, we're in a stronger position to transition than we would have been two or three years ago," Mr Obama told KDKA.
On the campaign trail, former House Speaker Newt Gingrich told CBS News the United States should leave Afghanistan as quickly as is feasible.
"My feeling is that we should leave. I think as fast as we can with safety. I think the possibility of us changing Afghan culture is virtually zero," Gingrich told congressional correspondent Nancy Cordes.
Additional reporting by Chloe Arensberg, David Martin and Carrie Rabin.