Three weeks ago anti-Gaddafi fighters dropped down from the Nafusa mountains in western Libya pushing back Gaddafi fighters from the plains below. <br /><br />The rebel fighters have managed to reach beyond the town of Bir Ayyad, less than 100 km from the capital Tripoli. <br /><br />But without the protection of the mountains, and with Gaddafi's forces thought to be arrayed across both flanks on the plains, the new frontline seems hard to defend. <br /><br />Al Jazeera's Jonah Hull reports from Libya.
