A soldier with a US-led military coalition fighting extremist rebels in Afghanistan and several militants were killed in separate clashes, the coalition said on Friday.
The soldier was killed "in action" on Thursday near the western town of Farah, the force said in a statement. It gave no details of what happened or the nationality of the soldier.
Most of the around 20,000 troops in the coalition are US nationals.
Sixty-five foreign soldiers have been killed in Afghanistan this year, according to an AFP count. Many of them were struck by improvised bombs.
The coalition reported separately that it had killed "several militants" and detained 16 on Thursday during a mission "to disrupt anti-government operations" in the central province of Ghazni.
Troops had gone to the Andar district to look for a militant who allegedly helped foreign fighters operate in Afghanistan and was involved in planting bombs aimed at troops, the statement said.
"During their search, Coalition forces were threatened by several militants and responded with small-arms fire, killing the militants," it said.
There has been a spike in recent weeks in violence linked to an insurgency led by the Taliban, who were in government between 1996 and 2001 and are now fighting to take back control.
Thousands of troops attached to Nato's International Security Assistance Force are also fighting against Taliban militants in an attempt to restore stability to the war-ravaged nation.