File picture shows fire rising from an oil tank in the port of Es Sider, in Ras Lanuf, Libya.

Suspected ISIS militants attacked oil installations close to Libya’s Ras Lanuf terminal on Thursday, an engineer at the port and an energy official allied with the country’s eastern government said, and the group threatened more attacks.

The officials said at least two storage tanks from the Harouge Oil Operations company had been set on fire near Ras Lanuf, where militants also launched attacks earlier this month.

ISIS fighter Abu Abdelrahman al-Liby said in a video posted on the group’s official Telegram channel: “Today Es Sider port and Ras Lanuf and tomorrow the port of Brega and after the ports of Tobruk, Es Serir, Jallo, and al-Kufra.”

The energy official, Mohamed al-Manfi, said a pipeline leading from the Amal oil field to the Es Sider terminal had been targeted. There were clashes between militants and Petroleum Facilities Guards, but Manfi and a guard’s source later said these had stopped and the militants had retreated.

A spokesman for the state-run National Oil Corporation based in Tripoli could not immediately be reached for comment.

Libya has become deeply divided since the fall of Muammar Qaddafi in 2011, with political and armed factions competing for power and for the country’s oil wealth.

ISIS militants have taken advantage of a security vacuum to establish a foothold in the city of Sirte, which lies about 200 km (125 miles) along the coast to the west of Ras Lanuf and Es Sider.

The terminals, Libya’s largest, have been closed since December 2014. The country’s oil production is less than a quarter of a 2011 high of 1.6 million barrels per day.

Clashes between Petroleum Facilities Guards and ISIS militants two weeks ago near Es Sider and Ras Lanuf left seven oil storage tanks damaged by fire and at least 18 guards dead.

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