U.S. Defense Secretary Leon Panetta says recent violence — including a deadly shooting spree outside Kandahar allegedly by a U.S. soldier — will not deter the United States from carrying out its mission in Afghanistan.

Pentagon spokesman George Little said Wednesday Panetta met with Afghan provincial officials during a visit to Afghanistan just days after the U.S. soldier allegedly murdered 16 civilians, including nine children.

Little said Panetta told the provincial leaders that such incidents do not represent the U.S. or Afghan people and security forces, “the vast majority of whom,” he said, are trying to do “the right thing.”

In Kandahar Wednesday, a motorcycle bomb killed one Afghan security officer and wounded at least two other people. No one has claimed responsibility, but the Taliban had vowed to avenge the recent murder of Afghan civilians.

President Barack Obama said the United States takes the incident as seriously as if it were its own citizens who were murdered. He said the killing of innocent civilians “is outrageous and unacceptable” and does not represent what the United States is.

He said he has extraordinary confidence in U.S. military leaders and troops. He reasserted that despite the public outrage, there will be no hasty U.S. retreat from Afghanistan.

The Taliban has threatened to behead Americans because of the murders. Taliban militants opened fire on a memorial service for the 16 villagers Tuesday in Kandahar, killing an Afghan soldier and wounding a policeman.

Hundreds of university students protested Tuesday in Jalalabad in the first significant public demonstration against the killings. Many of the marchers chanted “Death to America” and “Death to Obama.”

U.S. and Afghan officials say Sunday's carnage took place when a U.S. soldier walked off his base and shot and killed civilians in their homes in the Panjwai district of Kandahar. Villagers say he set some of the bodies on fire.