Iraq’s Oil Ministry has removed four oil services firms from a blacklist, including U.S. company Weatherford, after they agreed not to seek new contracts in Iraqi Kurdistan — the latest development in the federal government’s campaign to exercise control over the semi-autonomous region’s energy sector.

The director general of the state-run Basra Oil Company (BOC), Hassan Hassan, communicated the ministry’s decision in a letter dated Sept. 9 to “All Lead Contractors” at oil projects throughout Basra. Iraq Oil Report obtained a copy of the letter and confirmed its authenticity with an Oil Ministry official.