Libyan oil minister Mohamed Aoun sacked Mustafa Sanallah, chairman of the national oil company NOC, and appointed a new acting director.
The board of directors of the company will meet to elect a new chairman, a decree from the ministry said.
Recall that in September, Mr Aoun had suspended Mr Sanallah, accusing him of insubordination over his travels abroad without permission from the ministry.
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He was later reinstated by Prime Minister Abdel Hamid Dbeiba who overturned the suspension.