The raid was carried out a day earlier near Marzouk, an oasis some 600 miles (1,000 kilometers) south of the capital Tripoli, according to a statement released by Africom.

It said that its initial assessment indicated there had been no civilian casualties.

US forces, in coordination with the Libyan government, "conducted this airstrike to eliminate terrorist leaders and fighters and to disrupt terrorist activity," said Africom command Stephen Townsend, according to the statement.

"We will not allow them to use the current conflict in Libya as protection," he said. "Together with our Libyan partners, we will continue to deny terrorists safe haven in Libya."

The south of Libya is beyond the control of both the UN-backed Libyan Government of National Accord (GNA) and of its main rival, the self-styled Libyan National Army, despite claims by the latter's leader, military strongman Khalifa Haftar, to have a presence in the region.