The NATO-led force in Afghanistan says a man wearing an Afghan police uniform shot dead two of its soldiers in the country's south.
Britain's Ministry of Defense confirmed both soldiers were from the British Army's Royal Gurkha Rifles Regiment.
An Afghan police official in Helmand Province said that efforts were under way to find the attacker.
More than 50 members of ISAF have been killed this year in attacks in which members of Afghan security forces turn their weapons on their Western allies.
So-called insider attacks have undermined trust between coalition and Afghan forces as NATO allies prepare to withdraw most combat troops by the end of 2014.
Based on reporting by Reuters, AP, AFP