Two Afghan security personnel opened fire on Western colleagues Friday, killing two US soldiers and causing a number of other casualties in two separate attacks, the military said. US concern is mounting of the unprecedented number of such "green-on-blue" attacks, which have now killed 39 international troops in 29 such incidents so far this year, according to Nato figures.
Friday's attacks will further erode trust between foreign troops and the Afghans they work with, a week after six American troops were killed in a single day by their local colleagues.