Libya's El-Sharara oilfield, the country's largest, resumed production on Sunday, the National Oil Corporation (NOC) said.
NOC said the production was resumed after long negotiations.
On January 17, Khalifa Haftar's militia closed Az-Zuwaytinah port, claiming that oil revenues were being used by the internationally-recognised Government of National Accord.
"We hope that resuming production in the El-Sharara field will be the first step to restore life to the oil and gas sector in Libya, and a start to save the economy from collapse," NOC said in a statement.
Production will resume with a capacity of 30,000 per day with expectations to produce in full capacity within 90 days.
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El-Sharara oilfield produces more than 300,000 barrels of crude oil per day, forming roughly one third of the oil-rich country's production.
The move cames days after it liberated the strategic city of Tarhuna – the last stronghold of Haftar in western Libya. During the operation, the Libyan army seized weapons, ammunition, and vehicles purchased by the UAE for Khalifa Haftar's forces.
Libya holds Africa's largest crude reserves, but nine years of conflict and violence in the country since the 2011 ouster of ruler Muammar Gaddafi have hobbled production and exports. Libya's internationally recognised government has been under attack by Haftar's forces since April 2019, with more than 1,000 killed in the violence.
The government launched Operation Peace Storm in March to counter attacks on the capital and recently regained strategic locations, including the Al-Watiya airbase and Tarhuna, which is viewed as a significant blow to Haftar's forces.