[pjakma]

The US funnelled hundreds of millions of $ through Pakistan to help fund the Mujahideen in Afghanistan. The CIA also provided direct support, in training and weapons, etc.

https://en.wikipedia.org/wiki/Operation_Cyclone

Here's an Afghan with a Stinger missile (and there are lots of similar photos), not sold on the open market then, could realistically only have been acquired in bulk with US government assistance:

http://tkfiles.storage.msn.com/y1pUt0liKawcr-ryBplDmzAGeFbxG...