Oil production from Iraqi Kurdistan remains unaffected despite an incursion by Islamic State militants along the autonomous region’s border, its Ministry of Natural Resources said in a statement on Saturday.

The United States launched airstrikes in northern Iraq after Islamic State militants advanced to within a 30 minute drive from the regional capital Arbil, prompting oil companies in Kurdistan to withdraw staff and shut down some operations.

“Oil production in the region remains unaffected, and is being delivered to both the domestic and export markets,” the statement said.

“Indeed, the (regional government) is expecting that the producing companies will ramp up production in the coming weeks as ongoing export infrastructure improvements come online as planned.”

Total Kurdish production totaled about 360,000 barrels per day in June, according to the Paris-based International Energy Agency. About a third of that was exported, though Baghdad has been working to block sales outside its central system.

Iraqi Kurdistan-focused companies’ shares have fallen as investors reappraise the autonomous region’s security. Some of the biggest oil operators in the region have lost almost a quarter of their market value this week.

Abu Dhabi National Energy Co (TAQA), the state-owned oil explorer and power supplier, suspended activity at the Atrush Block in Kurdistan on Saturday due to the instability.

“Until now, the enemy has not been able to target oil operations in the region, but as a precautionary measure some of the exploration activities in areas abutting potential combat zones have been temporarily halted and staff relocated,” the statement said.

London-listed Afren and Toronto-listed Oryx said on Friday they were cutting production at oilfields closest to the fighting. U.S. oil major Chevron has also evacuated some staff from Kurdistan. An industry source said Exxon Mobil was doing the same.