Attacks by Afghan forces on international forces, so-called green-on-blue attacks, have left coalition partners wary of a prolonged military engagement in Afghanistan.
The U.S. Defense Department had said it was retooling its training programs considering the rise in the number of attacks by Afghan soldiers.
NATO Secretary-General Anders Fogh Rasmussen said, despite the issues, Afghan forces continue to show improvement on the ground. National forces, he said, are taking the lead as their troop strength passes the 350,000 mark.
"Right now, most ISAF units are conducting normal partnered operations," he said at a media briefing in Brussels. "They are working with our Afghan partners and they are mentoring our Afghan partners."
He admitted, however, that the International Security Assistance Force was going through "a challenging period." The French government had said it would pull its forces out of Afghanistan in 2013, a year early, following an insider attack in January that left four Frenchmen dead.
International forces are expected to wrap up their mission in Afghanistan by 2014.