Barack Obama has warned against "a rush for the exits" in Afghanistan as questions mount about US war strategy after a soldier's shooting rampage killed 16 civilians.
In a string of interviews on Monday to local television stations, the US president said the massacre would not change strategy or plans for keeping troops.
"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," Obama said. "But what we don't want to do, is to do it in a way that is just a rush for the exits."
"We have got hundreds of advisers in civilian areas as well, we have got huge amounts of equipment that have to be moved out. We have got to make sure that the Afghans can protect their borders to prevent Al-Qaeda coming back."
Obama said Sunday's incident is not comparable to the infamous My Lai massacre in Vietnam in which several US troops killed villagers and was seen as a turning point in that war.
Earlier on Monday, Afghanistan's parliament condemned the killing and said the nation had run out of patience with the arbitrary actions of foreign forces.
The Taliban, on its part, vowed revenge against the US in a statement posted on their website that said "American savages'' committed the "blood-soaked and inhumane crime'' in Panjwai district.
Just days before Sunday's attack, Kabul and Washington had made significant progress in negotiations on a Strategic Partnership Agreement that would allow American advisers and special forces to stay in Afghanistan after foreign combat troops leave at the end of 2014.
But securing a full deal may be far more difficult now after the shooting spree in the southern province of Kandahar, the Taliban heartland.
"This could delay the signing of the Strategic Partnership Agreement," an Afghan government official told the Reuters news agency.
Popular fury over the killing spree, which brought demands that the United States withdraw earlier than scheduled, could be exploited by the Taliban to gain new recruits.
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Anti-Americanism, which boiled over after copies of the Muslim holy book, the Quran, were inadvertently burned at a NATO base last month is likely to deepen after the Kandahar carnage.
"The Americans said they will leave in 2014. They should leave now so we can live in peace," said Mohammad Fahim, 19, a university student. "Even if the Taliban return to power our elders can work things out with them. The Americans are disrespectful."
The US war in Afghanistan is now in its eleventh year.