Iran has built an unmanned surveillance aircraft with a range of more than 600 miles (1,000 kilometers), long enough to reach Israel, a top Iranian defense official said in remarks published Wednesday. Deputy Defense Minister Ahmad Vahidi said he could not provide more details, only saying the development of the unmanned aircraft, or drone, was an "important achievement." His remarks were published Wednesday in the government-owned newspaper, Iran, and by the semiofficial Fars news agency. Iran announced two years ago it has built an unmanned aircraft, but Vahidi's comments were the first by a top official revealing its range. His claims could not be independently confirmed. Wednesday's reports follow this week's announcement that Iran has restructured its military in an effort to improve its air defense capabilities. The move was widely seen as part of a broader military build up by Teheran, which is concerned about the US military's presence in neighboring Iraq and Afghanistan and Israeli threats to target its nuclear facilities. Iran has taken Israeli threats to strike its nuclear sites seriously and has said Israel would be subject to Iran's "devastating retaliation" if it attacks. The first word of the drone came in 2007, when the then-commander of the Revolutionary Guards, Gen. Yahya Rahim Safavi, said the unmanned device was designed to take photos of and gather information about enemy positions. Iran also is seeking to develop a drone with attack capabilities. In December, air force commander Gen. Hasan Shah Safi said Iranian experts had designed an unmanned aircraft with radar-evading devices that would be able to attack an enemy target and avoid detection. He said the military was working on building a prototype of the craft. He did not elaborate on what sort of weaponry the craft would be fitted with. Since 2005, Teheran has accused the United States of flying surveillance drones over Iran's airspace to spy on its nuclear and military facilities. Iran says it is fighting an intelligence battle with the United States and Israel, which accuse Teheran of seeking to build nuclear weapons. Iran has denied the charges, saying its nuclear program is solely geared toward generating electricity. Iran launched an arms development program during its ruinous 1980-88 war with neighboring Iraq to compensate for a US arms embargo. Since 1992, Iran says it has produced its own jet fighters, torpedoes, radar-avoiding missiles, tanks and armored carriers.