Federal forces in Iraq have taken a refinery and the headquarters of the North Oil Company from the Kurdish military, an Iraqi official told Reuters.

The facilities are in the disputed province of Kirkuk.

On Monday, Iraq forces seized the city of Kirkuk, a flashpoint between the Regional Kurdish Government (KRG) and the central government. In response, the KRG halted production from the Kirkuk oil fields that it controls, Reuters reports. Production, however, was quickly resumed after the central government threatened military action to take over the fields, sources told Reuters.

Normal production is continuing despite the conflict, an official with the Iraqi Oil Ministry told Reuters, adding that “[w]e [the central government] have an agreement with some Kurdish leaders that the oil and gas facilities should stay out of the conflict.”

The Kurdish-controlled fields in Kirkuk have a daily output of 350,000 barrels per day (b/d) and account for more than half of the KRG’s oil production, according to Reuters.

The military action by the central government follows a recent non-binding independence referendum in the territories controlled by the KRG, including the province of Kirkuk.