Abu Salim is a district of Tripoli located in the south of the city. Located in the district is the Abu Salim prison.
Map of Abu Salim, Tripoli, Libya
It became a focal point of fighting during the Battle of Tripoli, as loyalists concentrated inside the area as over 1,000 rebels crowded around the Abu Salim district by 25 August.
References
Abu Salim (Tripoli district) Wikipedia(Text) CC BY-SA