article_snippet.sent: It wasn't immediately clear whether An Afghan soldier was among them.
article_snippet.sent: Other troops belong to the NATO-led Resolute Support mission meant to train and support Afghan troops.
article_snippet.sent: Most of the troops involved with Resolute Support are with the U.S. military.
article_snippet.sent: CNN national security analyst Peter Bergen said that despite Wednesday's incident, instances of "green-on-blue" attacks are declining overall for several reasons.
article_snippet.sent: First, there are far fewer US soldiers in Afghanistan," national security analyst Peter Bergen said.
article_snippet.sent: Second more counterintelligence resources were devoted to countering the threat and third, an attempt was made to better vet afghan army recruits.
article_snippet.sent: CNN's Masoud Popalzai and Jim Sciutto contributed to this report from Kabul, Afghanistan.