Opposition fighters have controlled the Libya-Tunisia border for almost three weeks, leaving gates open for those fleeing the conflict.
The uprising has spilled across the border numerous times, prompting the Tunisian government to send troops to the edge of the mountains.
All sides recognise the importance of this border, and Gadaffi forces are stationed in the mountains in an attempt to defend the border - and the battle is expected to be long and difficult.
Al Jazeera's Hoda Abdel-Hamid reports from the Libya-Tunisia border.
Source: Al Jazeera