TRIPOLI/DEHIBA, Tunisia (Reuters) – Forces loyal to Libyan leader Muammar Gaddafi overran a western rebel outpost on the Tunisian border on Thursday, with fighting spilling onto Tunisian territory, witnesses said.

The attack appeared to be part of a broader government move to root out rebel outposts beyond the confines of their eastern heartland. Rebels said the western mountain town of Zintan came under fire from multiple-launch Grad rockets seen as especially hazardous to civilian areas because of their inaccuracy.

Libyan rebels captured the Dehiba-Wazin border crossing to Tunisia a week ago and had since expanded their control to reach about 10 km (six miles) inside Libya from the crossing point. The counter-attack began with shelling of retreating rebels.

"Fighting broke out on the Tunisian territory, in Dehiba, after Gaddafi's forces attacked the border crossing," said Ali, a Tunisian involved in helping Libyans arriving in Dehiba.