Three US soldiers were wounded after an Afghan soldier opened fire at them inside an Afghanistan base, the NATO-led Resolute Support said on Sunday.
According to local media report, the Afghan soldier was shot dead after attacking the US soldiers.
Known also as "green-on-blue" attack, the insider attack, where an Afghan soldier or police fires on NATO coalition forces, is one of the major problems facing coalition forces there.
Last May, two Romanian soldiers were shot dead while training Afghan police.
Currently, around 13,000 foreign troops still remain in Afghanistan to train and assist local security forces in their fight against Taliban.