Oil has played a major role in Libya’s years-long war.
Most of the oil fields are in the country’s east, under the control of renegade military commander Khalifa Haftar’s forces.
This means the UN-recognised Government of National Accord in Tripoli has been cut off from a huge source of income.
On Friday, Haftar’s forces allowed a tanker to transport some of the crude for the first time in six months.
But they reimposed a blockade a day later.
Libya’s National Oil Corporation blamed Haftar’s backer, the United Arab Emirates (UAE), for the blockade.
The UAE says although oil production should resume, it wants “safeguards” in place to ensure revenues are not used to fuel the conflict.
Could the dispute scuttle attempts to end the war?