U.S. Army Sergeant Suspected in Afghanistan Shooting Allauddin Khan/Associated Press The bodies of several men and a child who witnesses said were killed by a United States Army sergeant in southern Afghanistan. PANJWAI, Afghanistan - Stalking from home to home, a United States Army sergeant methodically killed at least 16 civilians, 9 of them children, in a rural stretch of southern Afghanistan early on Sunday, igniting fears of a new wave of anti-American hostility, Afghan and American officials said. The man gathered 11 bodies, including those of 4 girls younger than 6, and set fire to them, villagers said. Coming after a period of deepening public outrage, spurred by the Koran burning by American personnel last month and an earlier video showing American Marines urinating on dead militants, the possibility of a violent reaction to the killings added to a feeling of siege here among Western personnel. Officials described growing concern over a cascade of missteps and offenses that has cast doubt on the ability of NATO personnel to carry out their mission and has left troops and trainers increasingly vulnerable to violence by Afghans seeking revenge. Early on Monday, the public mood in Kandahar and Kabul seemed subdued with no immediate sign of protests. Most of the dead were buried Sunday, with the final funeral scheduled for Monday. In a statement following the attacks Sunday, the Taliban threatened vengeance, as the insurgents often do after Western actions they depict as atrocities. President Hamid Karzai condemned the attacks, calling them in a statement an "inhuman and intentional act" and demanding justice. Both President Obama and Defense Secretary Leon E. Panetta called Mr. Karzai, expressing condolences and promising thorough investigations. "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," Mr. Obama said in a statement. American officials in Kabul were scrambling to understand what had happened, and appealed for calm, at a moment when the United States and Afghanistan are in tense negotiations on the terms of the long-term American presence in the country. The officials said the suspect was an Army staff sergeant who acted alone and then surrendered. "The initial reporting that we have at this time indicates there was one shooter, and we have one man in custody," said Lt. Col. Jimmie Cummings, a NATO spokesman. A senior American military official said Sunday evening that the sergeant was attached to a unit based at Joint Base Lewis-McChord, a major Army and Air Force installation near Tacoma, Wash., and that he had been part of what is called a village stabilization operation in Afghanistan. In those operations, teams of Green Berets, supported by other soldiers, try to develop close ties with village elders, organize local police units and track down Taliban leaders. The official said the sergeant was not a Green Beret himself. Another senior military official said the sergeant was 38 and married with two children. He had served three tours of duty in Iraq, this official said, and had been deployed to Afghanistan for the first time in December. Yet another military official said he has served in the Army for 11 years. In Panjwai, a reporter for The New York Times who inspected bodies that had been taken to the nearby American military base counted 16 dead, including five children with single gunshot wounds to the head, and saw burns on some of the children's legs and heads. "All the family members were killed, the dead put in a room, and blankets were put over the corpses and they were burned," said Anar Gula, an elderly neighbor who rushed to the house after the soldier had left. We put out the fire. The villagers also brought some of the burned blankets on motorbikes to display at the base, Camp Belambay, in Kandahar, and show that the bodies had been set alight. Soon, more than 300 people had gathered outside to protest. Taimoor Shah reported from Panjwai, and Graham Bowley from Kabul, Afghanistan. Reporting was contributed by Sharifullah Sahak, Rod Nordland and Matthew Rosenberg from Kabul; Eric Schmitt from Washington; William Yardley from Tacoma, Wash.; James Dao from New York; and Isolde Raftery from Seattle.