Iran warned the United States Sunday that it will take strong action against any further intrusion by the US into its airspace, Iranian media reported.
Sunday's strong warning comes 10 days after two Iranian jets shot at a US drone.
"Yes, we opened fire, and it was with warning shots. If they do it again they can expect an even stronger response," the Iranian Students News Agency quoted General Amir-Ali Hadjizadeh, head of Iran's Revolutionary Guards Air and Space Forces.
Hadjizadeh said Sunday: "This spy drone entered Iranian airspace and had to turn around because of the immediate reaction by fighters of the Revolutionary Guards".
"The drone was flying near Kharg Island and our understanding is that ... it was gathering economic information and intelligence on Kharg Island and oil tankers (in the area)."
"The Islamic Republic of Iran has some red lines that the Americans should understand and respect. If this is repeated, we will definitely react," Hadjizadeh added.
The Pentagon has said that the American drone was "never in Iranian airspace" and came under fire from Iranian Su-25 Frogfoot fighter jets off the Iranian coast over international waters.
But on Friday, Iranian Defense Minister Ahmad Vahidi said the drone had "entered the space over the territorial waters of the Islamic Republic of Iran in the Persian Gulf area."
Kharg, 15 miles off the Iranian mainland, is the Islamic republic's main export terminal for its oil.