21st Century US Gangs vs ISIS (The Islamic State)

Okay, so the battlefield is... I dunno, Los Angeles, and we've got every major US gang occupying LA at almost every street corner, city block, yada yada yada. Kinda like Batman: Arkham City. There's no cops, gangs have access to assault weapons such as AK-47s, sub-machine guns, etc, and familiar territory on their side. What if ALL of ISIS suddenly appeared and decided to seize LA?

Rules:

- ISIS has no tanks or APCs. Only technical vehicles.
- This is all current US gangs within the 21st Century. Including in-mates housed in federal prison.
- The ISIS fighting is ISIS at it's prime. Sources vary, but it's estimated to be between 52,600–257,900 total.

What happens?
Who wins?

I don't see this going well. We generally don't do threads like this. Sorry.