Following US military airstrikes over the weekend, the Federal Aviation Administration has issued a ban on US airlines flying over Iraqi airspace.
FAA officials said the ban would continue until further notice due to the "hazardous situation."
US airstrikes targeting ISIS forces in northern Iraq continued over the weekend, and the FAA expanded an earlier ban on US planes flying over the country to include flights above 30,000 feet.
Iraq airspace is a busy flight corridor for international airlines between Europe and the Middle East and Asia.
International airlines are also steering clear of the region.
British Airways has suspended flights over Iraq airspace and will "keep the situation under review."
Lufthansa, Air France-KLM and Virgin Atlantic have also rerouted flights away from the war-torn region in recent days.
The European Aviation Safety Agency last week urged European airlines to "exercise caution as a potentially hazardous situation may exist" due to the escalating conflict on the ground.
Delta and United Airlines, which serve destinations in the Gulf from the US, will be most affected by the ban, although Delta had already begun rerouting aircraft from the area.
