Libya's rebel-held Western Mountains have come under intense bombardment from Muamma Gaddafi's army, forcing rebels to pull back from the border with Tunisia as rockets slammed into the desert.

Rebels say it was the most sustained campaign for at least a week, which killed three of their men and wounded several others. At least four rockets landed in on the Tunisian side of the border and within several hundred meters of a crossing.

Dozens more mortar shells and rockets thumped into the mountainside in Libya. Tunisia has warned Libya it will refer Tripoli to the U.N. Security Council if it continues to commit "enemy actions".