The International Security Assistance Force said in a written statement the shooting in southern Afghanistan involved a gunman in an Afghan army uniform who opened fire on ISAF troops.
The incident was under investigation and the name and nationality of the slain soldier was not released.
The ISAF also reported it had captured three members of the insurgent group Haqqani in Paktiya province this weekend. Along with the trio, coalition raiders seized a pile of Afghan military uniforms and some hand grenades.
ISAF and Afghan security forces killed the leader of a Taliban "direct-action cell" in a clash in Helmand Province Saturday, the ISAF said.
The individual, identified as Zafran, was believed to be behind recent ambushes and bombings in the province. The ISAF statement said Zafran was working on plans for an IED attack on coalition forces when he was killed.