Libya’s National Oil Corporation has reinstated Shokri Ghanem as chairman, weeks after he left the post.

In September, Ghanem left the job for unknown reasons and was replaced with Ali Seghir Mohamed Saleh.

“Reinstated, and no other comment,” Ghanem told Reuters.

Ghanem’s exit followed an acrimonious dispute between Libya and Canadian oil explorer Verenex, reported Reuters.

Libya contains Africa’s biggest proved oil reserves and is a member of the Organization of the Petroleum Exporting Countries (Opec).