Three NATO troops and an Afghan soldier died in two separate clashes with insurgents in Afghanistan, the alliance said.
The identities of the NATO soldiers were not given.
Two of the NATO soldiers and the Afghan were killed on Friday in an area of eastern Nuristan province in a clash with Taliban rebels. Thirteen NATO soldiers were wounded in that incident.
The alliance said 24 insurgents were also killed in the Nuristan clashes. Fighting was still going on, the provincial governor said.
The governor, Tameem Nuristani, did not give further details.
A Taliban spokesman said only three insurgents were killed in the clashes and said the casualties of NATO and Afghan troops were higher than reported.
The third NATO soldier was killed in another encounter in the south of the country on Friday.
Violence has surged in Afghanistan in the past 18 months, the bloodiest period since the Taliban's overthrow in 2001.
Separately, four Afghan police were killed in an ambush on Saturday on a road in Logar province, which lies to the south of the capital Kabul, provincial police said.
Friday's deaths bring the number of foreign forces toll killed in action to over 90 this year in Afghanistan.