Gunmen also kidnapped 11 people in Tazerbo desert region, which is controlled by the forces of Libyan strongman Khalifa Haftar
At least nine security service officers were killed in a suspected Islamic State (IS) group attack in the southeastern Libyan town of Tazerbo on Friday, a senior security official said.
Eleven other people, including civilians and a security chief, were also kidnapped by gunmen thought to belong to the militant group, who attacked a police station in the oasis town, said the official.
The Tazerbo desert region is controlled by the forces of Libyan strongman Khalifa Haftar, who heads the self-styled National Libyan Army (LNA).
The capital Tripoli is the seat of a rival administration, the internationally-backed Government of National Accord (GNA), led by Fayez al-Sarraj.
Friday's assault, which is yet to be claimed by IS, is the second attack targeting forces loyal to Haftar in less than a month.
In October, an attack claimed by IS killed at least five people in the country's central Kufra region.
Another IS-claimed attack in August killed 11 people, including nine members of the LNA.
Torn apart by power struggles and undermined by chronic insecurity, Libya has become a haven for militants since the ouster and killing of Moammad Gaddafi in 2011.
IS took advantage of the chaos to gain a foothold in the city of Sirte in 2015, but forces loyal to the GNA regained control of the city in December 2016 after eight months of fighting.
Since then, some militants have returned to the desert in an attempt to regroup and reorganise.
In September, IS claimed responsibility for a suicide attack on the headquarters of the Libya's National Oil Company (NOC) in the heart of Tripoli, which left two dead and 10 wounded.