Artillery rounds fired by forces loyal to Libya's Muammar Gadhafi fell in Tunisia on Saturday as fighting broke out near the border between Libyan soldiers and anti-Gadhafi rebels.

Schools were evacuated and residents scurried for safety in the Tunisian frontier town of Dehiba, which has been hit repeatedly by stray shells in recent weeks as the Libyan rivals fight for control of a nearby border crossing.

Billows of dust and rock marked where at least four projectiles struck on the Tunisian side.

The battle is for control of the Dehiba-Wazzin border crossing, which gives the rebels a road from the outside world into strongholds in the Western Mountains region where they are fighting Gaddafi's forces.

Although the rebels hold that border point, Gadhafi's forces are in charge of a far bigger one to the north.

Over the past week, battles have intensified in the Western Mountains, one of several fronts in a Libyan war in which rival forces have fought to a position of bloody stalemate at a number of points.

Rebels fighting to end more than four decades of Gadhafi's rule have been aided by NATO airstrikes against loyalist heavy weaponry, but it has not been enough to give them a decisive edge.

Last week, fighting at the Tunisian border crossed into Dehiba itself, drawing furious protests to Libya from Tunisia's authorities.

More than 30,000 Libyan refugees have crossed from the Western Mountains into Tunisia, where many are being hosted by local families.

Sympathy for the Libyan rebels tends to be strong in Tunisia, where the ousting of an authoritarian president in January after 23 years in power sparked uprisings in Libya and across the Arab world.