U.S. oilfield services companies Schlumberger, Baker Hughes and Halliburton have pledged to comply with a federal supreme court ruling and withdraw from Iraq's Kurdistan region, the country's oil ministry said in Baghdad.

The companies have confirmed that they will not start new projects in the semi-autonomous Kurdistan region and are in the process of closing their existing tenders and contracts there, a ministry statement said.

"Baker Hughes has been committed to supporting Iraq’s energy needs for decades and we are keen to continue doing so in accordance with local laws and regulations," a Baker Hughes spokesperson said.

Halliburton and Schlumberger did not immediately respond to requests for comment.

The oil ministry statement follows months of disputes between Erbil and Baghdad after a February federal court ruling that deemed the legal foundations of the Kurdistan region's oil and gas sector to be unconstitutional. 

The oil ministry in Baghdad has since made fresh attempts to implement the ruling, including summoning seven firms operating there to commercial court sittings that have been postponed repeatedly. 

The ministry also wrote to lead contractors and sub-contractors in early June giving them three months to terminate existing contracts or projects in the Kurdistan Regional Government's (KRG) oil sector or face being blacklisted, two sources told Reuters in June.

The KRG has repeatedly rejected the federal court ruling.