Iran's official PressTV reported that the "Defenders of Velayat Skies 4" maneuver would cover 850,000 square kilometers in eastern Iran, and would "display the full strength and preparedness of Iran's air defense forces to defend the Islamic Republic's eastern borders."
Pentagon spokesman George Little said the Iranian planes fired at least twice at the slow-moving drone and pursued it for several miles as it moved away. He said at no point did the Predator enter Iranian airspace.
"There is absolutely no precedence for this. This is the first time that a [drone] has been fired upon to our knowledge by Iranian aircraft," said Mr. Little.
When he was asked if the Iranians might have fired only warning shots, Little replied: "Our working assumption is that they fired to take it down. You'll have to ask Iranians why they engaged in this action."
While both sides have engaged in heated rhetoric over Iran's controversial nuclear program, neither announced the drone incident last week until CNN broke the news on Thursday.
CNN reported a senior US official saying: "At least two bursts of gunfire came from the Su-25s' cannons. The drone started to move away but the Iranian aircraft chased it, doing aerial loops around it before breaking away and returning to Iran."