Militants from the so called Islamic State attacked forces guarding one of Libya’s main oil ports last Thursday with a gun assault and an attempted car bomb, in an escalation of their campaign in the North African state, a local security official said to Reuters.

Militants attacked guards at a gate near Es Sider (Sydra) port, which is under the control of forces allied with the recognized government, the security official said. The terminal has been closed since December because of fighting with other rival armed factions and problems at supply oilfields.

Islamic State has gained ground in Libya where two rival governments — one internationally recognized and the other self-declared — are battling for control, leaving a security vacuum four years after the uprising toppled Muammar Gaddafi.

Ali Hassi, spokesman for the a local battalion of the Petroleum Facilities Guard, a force allied with the official government, said one guard was killed and two more wounded, but he gave no details about how close the gate was to the port itself.

Militants later tried to target the same gate with a car bomb but failed and four of them were shot dead, he added.