Obama promises to use "full force of the law" in response to Afghan killings

President Obama, from the White House Rose Garden, speaks about the killing spree in Afghanistan. March 13, 2012

Updated at 12:22 p.m. ET

(CBS News) President Obama on Tuesday vowed to hold whoever was responsible for the killing spree in Afghanistan that left 16 civilians dead over the weekend "fully accountable," directing the Pentagon to "spare no effort" in conducting a full investigation to find out what happened.

"The United States takes this as seriously as if it were our own citizens and our own children who were murdered," Mr. Obama said from the White House Rose Garden. "We're heartbroken over the loss of innocent life."

A U.S. soldier, now in U.S. custody, has been accused of killing the civilians in their homes in the middle of the night between Saturday and Sunday and then burning some of their corpses. Afghan President Hamid Karzai said nine of those killed were children and three were women.

Mr. Obama called the killings "outrageous and unacceptable" and said, "It's not who we are as a country, and it does not represent our military."

"We will make sure anybody who was involved is held fully accountable with the full force of the law," he added.

Mr. Obama met on Monday with the top American military commander in Afghanistan, General John Allen, and U.S. Ambassador to Afghanistan Ryan Crocker, and the president said Tuesday he has "extraordinary confidence" in them as well as the troops in Afghanistan. Mr. Obama meets later Tuesday with British Prime Minister David Cameron and will discuss the way forward in Afghanistan in preparation for the upcoming NATO summit.

"Make no mistake," Mr. Obama said. "We have a strategy that will allow us to responsibly wind down this war. 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."

In a set of interviews with local broadcast stations on Monday, Mr. Obama stressed that there shouldn't be a "rush for the exits" in Afghanistan in the wake of tragedies like this killing spree. He said the incident wouldn't impact the timetable for the United States and its NATO allies to hand over security control to the Afghans by the end of 2014.

Today, Mr. Obama noted that the U.S. is scheduled to remove 23,000 troops by the end of this summer, following the 10,000 that were withdrawn last year.There are now about 91,000 U.S. forces in Afghanistan.

"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," he said.