Iran's armed forces have shot down an unmanned U.S. spy plane that violated Iranian airspace along the country's eastern border, the official IRNA news agency reported Sunday. But a U.S. defense official said there was no indication it was brought down by hostile fire.
An unidentified military official quoted in the report warned of a strong and crushing response to any violations of the country's airspace by American drone aircraft.
"An advanced RQ-170 unmanned American spy plane was shot down by Iran's armed forces. It suffered minor damage and is now in possession of Iran's armed forces," IRNA quoted the official as saying.
In a statement, the NATO-led International Security Assistance Force in Afghanistan acknowledged that a surveillance drone had gone out of control last week.
"The UAV to which the Iranians are referring may be a U.S. unarmed reconnaissance aircraft that had been flying a mission over western Afghanistan late last week," the statement said. "The operators of the UAV lost control of the aircraft and had been working to determine its status."
A U.S. defense official said there was "no indication it was brought down by hostile fire."
Iran is locked in a dispute with the U.S. and its allies over Tehran's disputed nuclear program, which the West believes is aimed at developing nuclear weapons. Iran denies the accusations, saying its nuclear program is entirely peaceful and that it seeks to generate electricity and produce isotopes to treat medical patients.
The type of aircraft Iran says it downed, an RQ-170 Sentinel, is made by Lockheed Martin and was reportedly used to keep watch on Osama bin Laden's compound in Pakistan as the raid that killed him was taking place earlier this year.
The surveillance aircraft is equipped with stealth technology, but the U.S. Air Force has not made public any specifics about the drone.
Iran said in January that two pilotless spy planes it had shot down over its airspace were operated by the United States and offered to put them on public display.
The Islamic Republic holds frequent military drills, primarily to assert an ability to defend against a potential U.S. or Israeli attack on its nuclear facilities.
Tehran has focused part of its military strategy on producing drones for reconnaissance and attacking purposes.
Iran announced three years ago it had built an unmanned aircraft with a range of more than 600 miles (1,000 kilometers), far enough to reach Israel.
Ahmadinejad unveiled Iran's first domestically built unmanned bomber aircraft in August 2010, calling it an "ambassador of death" to Iran's enemies.
Material from The Associated Press was used in this report