The U.S. along with Saudi Arabia, Israel and others. Also, they have an extensive in with the global Heroin trade. This is why they took over that city in the Philippines, protecting their heroin trade, that, by the way, runs through the Albanian mafia.
I covered this in an article here on Steemit last month.
https://steemit.com/politics/@goldgoatsnguns/eastern-europe-is-a-powder-keg-arming-isis
Haven't read that article, but ISIS supporting itself with drugs is just another argument for total drug legalization. If it was legal, then there would be a lot less profit in it.