WASHINGTON (AP) -- U.S. officials were scrambling Sunday to contain the damage caused when an American soldier in Afghanistan wandered off base and allegedly gunned down more than a dozen villagers.
President Barack Obama and Defense Secretary Leon Panetta both called Afghan President Hamid Karzai to express their condolences and vowed to hold those responsible accountable. Afghan officials reported that 16 people were killed including nine children and three women.
"This incident is tragic and shocking, and does not represent the exceptional character of our military and the respect that the United States has for the people of Afghanistan," Obama said in a statement released by the White House.
Caitlin Hayden, a spokeswoman for the White House National Security Council, said Obama called Karzai shortly after meeting Sunday afternoon with his top national security advisers.
Panetta said a full investigation was already under way.
"A suspect is in custody, and I gave President Karzai my assurances that we will bring those responsible to justice," he said.
Gen. John Allen, the top U.S. commander in Afghanistan, issued a statement pledging a "rapid and thorough investigation" into the shooting spree, and said the soldier will remain in U.S. custody.
U.S. officials said the service member was being detained in Kandahar and the military was treating at least five wounded. One U.S. official said the soldier, an Army staff sergeant, was believed to have acted alone and said initial reports indicated he returned to the base after the shooting and turned himself in.
The shootings come at a particularly sensitive and critical time for the U.S., just as violence over the burning of Muslim holy books at a U.S. base was starting to calm down. Sunday's incident could further fuel calls for a more rapid withdrawal of U.S. troops from Afghanistan.
The destruction of Qurans in a fire pit used to burn garbage last month sparked violent protests that killed some 30 people. Six U.S. service members were killed in attacks by Afghan security forces since that incident, which U.S. officials have apologized for and said was accidental.
Allen, in his statement, offered his regret and "deepest condolences" to the Afghan people for the Sunday shootings, and vowed that he will make sure that "anyone who is found to have committed wrongdoing is held fully accountable."
"This deeply appalling incident in no way represents the values of (the International Security Assistance Force) and coalition troops or the abiding respect we feel for the Afghan people," said Allen. "Nor does it impugn or diminish the spirit of cooperation and partnership we have worked so hard to foster with the Afghan National Security Forces."