Local authorities said on Tuesday that the incident took place at Camp Zafar in the provincial capital of Herat, located 650 kilometers (400 miles) west of Kabul, on Monday.
The incident happened when an Afghan army member opened fire on the US-led forces, English-language newspaper Outlook Afghanistan reported.
Commander of the 207th Corps Taj Mohammad Zahid said an interpreter was also injured during the shootout, adding that the assailant was killed by Afghan army soldiers.
ISAF has confirmed the incident, adding that an investigation into the shooting is underway.
The latest attack by Afghan security forces on foreign troops comes at a sensitive time for the United States and its allies amid preparations to withdraw the majority of their troops by the end of 2014 under a plan that requires Afghan forces to take responsibility for the country’s security.
According to official figures released by the website icasualties.org, the overall number of the US-led soldiers killed so far this year in Afghanistan stands at 63, of which 44 have been American.
A total of 161 US-led soldiers lost their lives in Afghanistan in 2013. However, 2010 remains the deadliest year for US-led military casualties, with a death toll of 711.
The US and its allies invaded Afghanistan in 2001 as part of Washington’s so-called war on terror. The offensive removed the Taliban from power, but insecurity continues across the country despite the presence of thousands of US-led troops.
The US-led war in Afghanistan, which has caused record-high civilian and military casualties, has become the longest military conflict in US history.