Three U.S. soldiers were killed in Afghanistan on Saturday when a man in an Afghan army uniform turned his weapon on them in the eastern province of Paktik
Insider attacks accounted for one in every five combat deaths suffered by NATO-led forces in Afghanistan and 16 percent of all American combat casualties, according to 2012 data.
The toll has alarmed Afghanistan's Western allies and raised troubling questions about the unpopular war's direction as most international forces prepare to withdraw by the end of next year.
Last year, a surge in such attacks prompted NATO to temporarily curtail some joint operations with Afghan government forces.
In the insider attack, which took place at a base in Paktika Province near the border with Pakistan, a soldier with the Afghan National Army opened fire during lunchtime, killing two of the American soldiers serving with him and the civilian
Last year, 48 insider attacks killed 64 international troops and civilians working with the military.
The second attack on Saturday took place in Farah Province in western Afghanistan as two men on a motorcycle threw a grenade at a group of Italian soldiers, killing one and wounding two others, the attack took place as the convoy of Italians was heading back from the provincial capital