Sunni Muslim insurgents from an al Qaeda splinter group forced the shutdown Tuesday of Iraq’s largest oil refinery.
The refinery in Baiji is about 50 miles north of the city of Tikrit.
Last week, fighters from the Islamic State of Iraq and Syria (ISIS) overran Tikrit and Iraq’s second city, Mosul.
A refinery official told Reuters the facility was shut down Monday night and foreign staff was evacuated.
Iraq has only three refineries.
The Baiji refinery — the biggest in the country — has a capacity of up to 310,000 barrels of oil a day.
Iraq is OPEC’s second-biggest oil producer.