An Afghan teenager fatally stabbed an American soldier in the neck as he played with children in eastern Afghanistan, officials said Monday, as the U.S. death toll rose sharply last month with an uptick in fighting due to warmer weather.

Last week’s calculated attack shows that international troops still face a myriad of dangers even though they are increasingly taking a back seat in operations with Afghan forces ahead of a full withdrawal by the end of 2014.

Just one U.S. service member was killed in February — a five-year monthly low — but the American death toll climbed to at least 14 last month.

Overall, the number of Americans and other foreign forces killed in Afghanistan has fallen as their role shifts more toward training and advising government troops instead of fighting.

But a series of so-called insider attacks on foreign troops by Afghan forces of insurgents disguised as them has threatened to undermine the trust needed to help President Hamid Karzai’s government take the lead in securing the country after more than 11 years at war.

The attack that killed Sgt. Michael Cable, 26, of Philpot, Ky., Wednesday occurred after the soldiers had secured an area for a meeting of U.S. and Afghan officials in a province near the volatile border with Pakistan.

But one of two senior U.S. officials who confirmed that Cable had been stabbed by a young man said the assailant was not believed to have been in uniform so it was not being classified as an insider attack.

The officials, who spoke on condition of anonymity because the investigation is ongoing, said the attacker was thought to be about 16 years old. He escaped so his age couldn’t be verified.

Cable’s brother Raymond Johnston, a 42-year-old waiter in Owensboro, Ky., said the Army told the family the basics of what happened and that his brother was stabbed in the neck from behind.

Johnston said his brother, who also did a tour of duty in Iraq, was “prepared before he left for anything that happened” in Afghanistan.

Cable met individually with Johnston and three other family members before leaving for Afghanistan and had similar conversations with each — that the deployment was extremely hazardous and that his family and friends should “continue to enjoy life” if he was killed.

“He was able to communicate to the family about if the worst was supposed to happen, what we were supposed to do,” Johnston said.

Cable’s body was scheduled to return to Owensboro in western Kentucky on Thursday. Visitation was scheduled for Friday with the funeral set for Saturday.

The soldier was playing with children outside when the attacker came from behind and stabbed him in the neck with a large knife, senior district official Zalmai Khan said. Other guards nearby didn’t immediately notice what had happened because there was no gunshot, and the assailant was able to flee to neighboring Pakistan, he added.

Taliban spokesman Zabiullah Mujahid identified the attacker as a 16-year-old local boy named Khalid. He said Khalid was acting independently when he killed the soldier but had joined the Islamic militant movement since fleeing the scene.

Khan did not provide a name or confirm the Taliban’s claim.