edit: at the same time, in the same conflict.
I remember reading a few years ago about a conflict in (I want to say) 1980’s Latin America where this occurred; however I can’t find anything about this with current online search tools. Did I hallucinate this or did this actually, and if so what groups?
Maybe the United States involvement in regime change in Latin America is what you had in mind?
Or perhaps you’d like to peruse through old CIA files.