NATO officials in Afghanistan says a man in an Afghan army uniform has shot and wounded five coalition troops at a military base near Kabul.
The attack occurred Tuesday in the Syed Abad District of restive Wardak province.
An Afghan military spokesman says the shooter fled the area.
The attack raises the number of so-called "green-on-blue" (Shooters in Afghan uniform attacking NATO troops) incidents this year to 19. At least 23 NATO soldiers have died in the attacks.
Earlier this week, an Afghan man dressed in a police uniform killed three British soldiers at a checkpoint in southern Afghanistan's Helmand Province.
The growing number of these attacks has raised questions as NATO works to transfer full security responsibility to Afghan forces by 2014.
U.S. data released this year show that at least 60 percent of the attacks are motivated by personal issues.