At least 13 people, including five foreign nationals, were killed when gunmen stormed a remote oilfield in northern Libya on Wednesday, according to media reports. A security official at the al-Mabrook oilfield, about 105 miles south of the Mediterranean coastal city of Sirte, reportedly said that militants allied to the Islamic State group were behind the attack.

“Eight Libyans, three Filipinos and two Ghanians were killed in the attack … all of them had their throats slit apart from one Libyan, who was shot dead,” Hakim Maazzab, a senior security official at the oil complex, managed by the state-run National Oil Corporation, told Agence France-Presse (AFP). He added that his men were back in charge of the complex after the gunmen fled the area.

The oilfield, which is part-owned by Total -- a French oil and gas company -- has remained closed since December, following clashes between rival militias that shut the Es Sider oil port. Total said that it had already withdrawn staff from the site in 2013 and had no personnel at the oilfield since July 2014, according to media reports.

Libya has been in a state of turmoil since armed rebels, belonging to a group known as Libya Dawn, took control of Tripoli last summer and established a rival government. The country’s internationally recognized government, headed by Prime Minister Abdullah al-Thinni, has been pushed to the eastern city of Tobruk. Several other armed groups, including one led by renegade General Khalifa Hifter, are also fighting for power in the deeply-divided country.

The attack comes a week after militants, allegedly loyal to ISIS, stormed a hotel in the capital city of Tripoli and killed at least 10 people, including an American and a French national. Although Libyan government officials have so far not acknowledged ISIS’ presence in the country, in recent months, several reports hinting at the militant group’s expansion in the country have emerged. Factions of local Sunni groups, including Ansar al-Sharia and al Qaeda in the Islamic Maghreb, have also pledged loyalty to ISIS.