A Pentagon official says an Iranian fighter jet approached a U.S. surveillance drone aircraft over the Gulf but broke off its pursuit after a U.S. plane escorting the drone discharged a flare to warn the Iranian pilot.

Pentagon press secretary George Little said Thursday that the incident occurred Tuesday. He said the unarmed Predator surveillance drone as well as two U.S. military aircraft that were escorting it remained over international waters at all times.Little said the drone was conducting what he called a "routine classified" surveillance mission.He said the Iranian F-4 plane came as close as 16 miles (25 kilometers) to the drone before it broke away.In November an Iranian fighter fired upon, but did not hit, a Predator over the Gulf.