Libya’s state oil company suspended shipments from two key eastern ports, according to people familiar with the matter, amid a worsening political crisis in the OPEC member.

The National Oil Corp. informed some trading and shipping firms on Tuesday of force majeure restrictions at Es Sider and Ras Lanuf, the country’s largest and third-biggest export terminals respectively, the people said.

The move came a day after the NOC said it may have to halt exports from the Gulf of Sirte, which includes both ports, as well as Brega and Zueitina. Waha Oil Co., which uses Es Sider, has completely shut down production because local protests prevented tankers from loading crude.

The NOC didn’t immediately respond to a request for comment.

The drop in Libya’s supply is further tightening the global oil market. Crude prices have soared 50% this year to around $115 a barrel, largely due to the fallout of Russia’s invasion of Ukraine. Many major producers are also struggling to sustain their output.

Libya’s crude production has halved since mid-April to roughly 600,000 barrels a day, according to Bloomberg estimates.

Loadings from Ras Lanuf this month have been revised down to 1.8 million barrels from a previous plan of 3 million barrels, according to a program seen by Bloomberg. 

The country’s been mired in conflict since the fall of dictator Moammar Al Qaddafi in 2011. It is now grappling with protests that have forced many oil fields and ports to shut down.

There’s a standoff between two politicians—Abdul Hamid Dbeibah and Fathi Bashagha—who each claim to be the legitimate prime minister. The recent closures are linked to politics, with protesters at energy facilities demanding the transfer of power to Bashagha.