A plan to start delivering F-16s to Iraq in September is on hold until the security situation improves, a U.S. official said.

Last month, the U.S. evacuated contractors building the base for the F-16s at Balad as Sunni militants took large swathes of Iraq.

Currently, 18 Iraqi pilots are training in the U.S. to fly F-16s, including 12 flying F-16s at Tucson, Ariz., according to Air Education and Training Command. […]