Two US marines were killed and one wounded when their patrol was ambushed during an operation against Islamic militants in eastern Afghanistan.
The soldiers were killed in Kunar province, which borders Pakistan, on Thursday evening, said a military spokeswoman.
She said the wounded Marine was hurt by gunfire, but she said she did not know how the two were killed.
The attack happened in a mountainous district called Naray close to the border with Pakistan, residents there said. They said they saw the bodies of the two Marines and they appeared to have been shot with AK-47 assault rifles.
A military commander in Kunar's capital Asadabad, said the Marines came under fire as they were moving through a valley.
The deaths took to 59 the number of US personnel killed in combat in Afghanistan since US-led forces overthrew the Taliban.