BENGHAZI: Libya's local Islamic State affiliate says it has detonated two car bombs at a checkpoint near the country's oil fields and clashed with fighters allied with the internationally recognised government there.

Ali al-Hassi, a spokesman for the forces that control the majority of Libya's oil fields, says six of their fighters were killed in Monday's attacks, along with five IS fighters in the coastal port town of Siddra.

The extremist group has long had its eye on the fields, which lie east of its coastal stronghold of Sirte. In a statement circulated online, the group said Monday's operation was named after one of their slain leaders: Abu Mughira al-Qahtani.

Al-Qahtani was allegedly killed by a US airstrike two months ago in the eastern city of Darna.