ISIL terrorists killed eight guards on Friday in an attack on the southern Libyan oilfield of Al-Ghani, a spokesman for the unit tasked with guarding oil installations said.

ISIL terrorists killed eight guards on Friday in an attack on the southern Libyan oilfield of Al-Ghani, a spokesman for the unit tasked with guarding oil installations said.

"Extremists from the Libyan subsidiary of ISIL mounted a surprise attack on the oilfield, killing eight soldiers," Ali al-Hassi said.

Libya's National Oil Company also confirmed the attack.

An NOC spokesman, Mohamed al-Hrari, said that two foreigners, an Austrian and a Filipino who worked for a services company, were missing after the attack.

An earlier NOC statement said unidentified gunmen rampaged through buildings and other infrastructure and set fires, adding that staff were unharmed because they had fled.

Columns of smoke from the burning oilfield could be seen as far as the town of Zela, 60 kilometres (40 miles) away, the statement said.

Hassi said government forces later recaptured the oil installation, and that reinforcements were sent from nearby oilfields.