Responding to the UN backed government in Libya’s request for help against ISIS, the US began bombing strategic areas in Libya.
Ironically the core stronghold of ISIS is the hometown of former Libyan leader Muammar Gaddafi. Sirte is extra important to ISIS as it is a Mediterranean coastal city across the sea from Europe. This makes the second most important conquest outside of Syria and Iraq.
The US bombing campaign is focused mainly on pushing the ISIS militants from Sirte in order to allow the Libyan government to go in and take over.