In a statement Friday, the agency said all commercial airlines must avoid the area, effective immediately.
An FAA spokeswoman said that only one U.S. airline, cargo carrier Atlas Air, had been flying over Iraqi airspace.
The agency said it will reevaluate the order by the end of the year.
The announcement came just hours after U.S. fighter jets bombed Sunni militant forces in the northern part of the country, the first major
The FAA had previously restricted all U.S. airlines from flying 30,000 feet or lower over Iraq. Before that, the agency had barred flights below 20,000 feet over the country since July of last year.