Forces controlled by Libya’s eastern-based military commander Khalifa Haftar said they had retaken two of the country’s major oil terminals, after more than a week of fighting that curbed production and heightened tensions in the holder of Africa’s largest crude reserves.

The ports of Es Sider and Ras Lanuf, a petrochemicals factory and the nearby Harouge storage tanks had all been recaptured on Tuesday in a land, air and sea offensive, said Miftah Al Magaraif, head of a Petroleum Facilities Guard faction loyal to Haftar. His Libyan National Army announced its full control of the ports on its official Facebook page. The installations were seized from Haftar earlier this month by a rival group, which later said it handed them to the United Nations-backed government in Tripoli.

More than a year after a UN-mediated peace deal meant to end years of conflict and economic ruin that have followed the ousting of Muammar Qaddafi, Libya remains deeply divided, primarily between administrations in the west and east. Killings, kidnapping and smuggling are common. The latest fighting is a setback for political efforts to restore stability and plot an economic recovery. Control of oil assets would provide leverage in future talks on ending Libya’s crisis and have been a key focus of competing factions.

There was no immediate comment from the UN-backed administration. Late on Monday, the head of the Petroleum Facilities Guard units affiliated with it had called for international help to enforce a no-fly zone over the Gulf of Sirte, home to Es Sider, Libya’s largest export terminal for oil. The media office of Prime Minister Fayez al-Serraj’s Presidential Council said Haftar had been targeting the oil facilities since Sunday.

Powerful Allies

Before Haftar’s forces announced the success of its offensive, Jadalla Alaokali, a board member at National Oil Corp., said by phone that no damage to oil infrastructure had been reported so far.

Though he’s opposed by militias across central and western Libya, where 70 percent of the population lives, Haftar has powerful friends in the standoff with Serraj—Russia, Egypt and the United Arab Emirates are major backers. He also has widespread support in Libya’s east. The quick capture of the oil ports on March 3 by the Benghazi Defense Brigades was seen by many analysts as a blow to Haftar’s image. His popularity had soared last September when he seized the facilities and allowed oil to flow.

Exports from Es Sider and Ras Lanuf were suspended as the Benghazi militias advanced early this month. Crude production halted at Waha Oil Co., which pumps crude to Es Sider, pushing output down by 13 percent to 602,900 barrels a day, according to Alaokali. Waha is a joint venture between the NOC, Hess Corp., Marathon Oil Corp. and ConocoPhillips.

Under UN regulations, the Serraj government is the only entity allowed to sell oil, and export revenues go to the Tripoli central bank.