United States service member walked out of a military base in a rural district of southern Afghanistan on Sunday and opened fire on three nearby houses, killing at least 15 civilians, local villagers and provincial officials said. Related Security Fears Lead Groups to Rethink Work in Afghanistan (March 11, 2012) U.S. and Afghanistan Agree on Prisoner Transfer as Part of Long-Term Agreement (March 10, 2012) Afghan Officer Sought in Killing of 9 Colleagues (March 9, 2012) Connect With Us on Twitter Follow @nytimesworld for international breaking news and headlines. Twitter List: Reporters and Editors Readers’ Comments Share your thoughts. Post a Comment » Read All Comments (1) » The shooting risks further inciting anti-American sentiment in Afghanistan and troubling a relationship that had already been brought to a new low by the burning of Korans at an American military base last month. The American embassy in Afghanistan quickly issued a statement on Sunday urging calm. The NATO-led coalition said in a statement on Sunday that a United States service member had been detained after an incident in Kandahar Province, in the south of the country, and that a number of civilians had been killed. Villagers in Belandi in the Panjway district of Kandahar, where the shooting took place, said the service member had attacked three houses, killing 11 people in one house and four in a second home. Five other villagers were wounded, they said. Panjway, a rural suburb of Kandahar, was traditionally a Taliban stronghold. It was a focus of the United States surge in 2010 and was the scene of heavy fighting. The governor of Kandahar Province, Tooryalai Wesa, condemned the shooting, although he could not immediately confirm the number of people killed. A coalition spokesman in Kabul, Capt. Justin Brockhoff, said that it was not clear what had led to the incident. He said the civilians wounded in the shooting were taken to a coalition hospital where they were being treated. One of the houses attacked in the village belonged to a tribal elder, according to a person from the village. “We don’t know why he killed people,” said the villager, Aminullah, who like many Afghans goes by a single name. Aminullah said the soldier was alone. “There was no fighting or attacks.” In the statement, the United States military raced to head off Afghan outrage. “This is a deeply regrettable incident and we extend our thoughts and concerns to the families involved,” the statement said. It went on to say that American forces, in cooperation with the Afghan authorities, would investigate the incident. In its comments, the American Embassy also sought to ease tensions, offering “its deepest condolences to the families of the victims of today’s tragic shooting.” “We are saddened by this violent act against our Afghan friends,” the statement said. In a separate incident, four Afghans were killed and three wounded on Friday when coalition helicopters apparently hunting Taliban insurgents fired instead on villagers in Kapisa province in eastern Afghanistan, according to Abdul Hakim Akhondzada, governor of Tagab district in Kapisa. Last month, the burning of the Korans touched off nationwide rioting and increased the targeting of American troops, resulting in at least 29 Afghans dead and 6 American soldiers killed. The results of the official military inquiry into the Koran burnings are still awaited, including any decision on what kind of disciplinary action may be faced by the American service members identified as being directly linked to the incident. The upheaval provoked by the Koran burnings put a temporary halt to cooperation between the Afghans and Americans, and disrupted planning for the military withdrawal. But relations seemed somewhat back on track after the two governments on Friday broke an impasse on a long-term strategic partnership deal by agreeing for the Afghans to assume control of the main coalition prison in six months. In another incident in January, American officials had to contend with the fallout from a video that showed four United States Marines urinating on the corpses of what appeared to be the corpses of three Taliban members. In 2010, a rogue group of American soldiers, whose members patrolled roads and small villages, also near Kandahar, killed three Afghan civilians for sport in a series of crimes. The soldier accused of being the ringleader of the group was convicted of three counts of murder by an American military panel in November.