Libyan rebels have clashed with Sudanese mercenaries fighting for Muammar Gaddafi near the border with Sudan.
A commander said rebel fighters had destroyed a weapons-laden vehicle belonging to a Sudanese mercenary force about 20 miles west of the oasis of Kufra.
The rebels had surrounded and were trying to capture six other Sudanese vehicles mounted with heavy weapons, he said.
In previous clashes at the southern border, captured Sudanese mercenaries have said they belonged to the Darfur-based rebel group, the Justice and Equality Movement.
Gaddafi has long provided arms, training and vehicles to various rebel groups in Sudan.
Witnesses in Libya have reported African mercenary fighters shooting at protesters or being captured by anti-Gaddafi forces. Some were flown in to put down the rebellion, but most fighters were already in the war-torn country.
Gaddafi has used Libya's oil wealth to aid neighbouring African nations, including Sudan, and to fund the transformation of the old Organisation of African Unity into the African Union, which has helped resolve conflicts on the continent. In February, the AU condemned attacks on civilian protesters in Libya.
Meanwhile, in Nato airstrikes overnight, British aircraft hit four of Gaddafi's armoured vehicles near the Libyan city of Zlitan. Tornado and Typhoon jets also destroyed a radar station in the coastal city of Brega during the raid.
Libya's deputy foreign minister, Khaled Kaim, called on the South African leader Jacob Zuma to push forward negotiations to end the three-month conflict when he arrives next week in the capital Tripoli.
Mr Zuma is the highest-ranking politician to visit Gaddafi since the fighting began in Libya.