Musburger1
2,500+ Posts
These are "Shia" Iraqi militias. As such, they are not opposed to Assad, and understand that his defeat would result in the "occupation" of Syria perhaps by hostile radical Suni jihadists as well as permanent US bases within Syria next to the Iraqi border. These militias are only working with the US inside Iraq because the presence of ISIS is a greater threat than the presence of the US. But they (justifiably) hate our guts.