By . Craig Mackenzie . Last updated at 2:42 PM on 16th December 2011 . The unmanned U.S. spy plane captured by Iran appears to be a fake, a former Pentagon official has claimed. It is the wrong colour and  the welding along the wing . joints does not appear to conform to the stealth design that helps it . avoid radar detection, he said. But U.S. military officials have told CNN the drone was on a surveillance mission of suspected nuclear sites in the country. Scroll down for video . Drone or fake? Iranian military officials examine the craft after putting it on display . Iran's Islamic Revolutionary Guard Corps flaunted video footage of a downed plane which they claim had 'violated their air space.' on December 4th. They said it was a U.S. bat-winged RQ-170 Sentinel and boasted they guided it down electronically by hacking into its GPS system. But the ex-Pentagon worker, who does not wish to be named, questioned why the landing gear was covered up when displayed by the Iranian military. The drone's underside is obscured with banners that read: 'We'll trample America underfoot' and 'The U.S. cannot do a damn thing.' On Wednesday, state TV reported that data was still be recovered by Iranian engineers from the Sentinel, which is regularly used in stealth missions. The day before, another U.S. drone, the MQ-9, . reportedly crashed at Seychelles International Airport on the island of . Mahe after developing engine problems. Captured: Iran says it will not return the RQ-170 Sentinel reconnaissance drone that crashed in Iran this week . According to the Christian Science Monitor, Iranian scientists guided the RQ-170 to ground by 'spoofing' its GPS coordinates - tricking the plane into landing in Iranian territory instead of where it was programmed to touch down. An article in the Christian Science Monitor quoted an unnamed Iranian engineer who claimed he had been studying the inner workings of the captured RQ-170 Sentinel. He said the 'spoofing' technique made the craft 'land on its own where we wanted it to, without having to crack the remote-control signals and communications' from the U.S. control centre. Monitor writer Scott Peterson and an Iranian journalist publishing under the pen name Payam Faramarzi said the GPS weakness of aircraft has long been known to U.S. military officials. They cited a 2003 report titled GPS Spoofing Countermeasures that appears to warn of the type of attack claimed by the Iranian engineer. 'A more pernicious attack involves feeding the GPS receiver fake GPS signals so that it believes it is located somewhere in space and time that it is not,” says the report. 'This attack is more elegant than jamming because it is surreptitious.' The drone is used for covert surveillance such as the operation to spy on the Pakistan compound of Osama bin Laden before he was killed in a U.S. raid in May. U.S. officials have blamed the loss of the sophisticated spy plane on a malfunction, but have yet to explain how it was in such pristine condition after its recovery by the Iranians. U.S. and NATO officials have said it was on a mission to patrol the Afghan-Iran border and had veered off course when it went missing. Now military officials have told CNN that the Afghan government was unaware of the use of its territory to fly surveillance drones over Iran. The CIA had not informed the Defense Department of the drone's mission when reports first emerged that it had crashed. One official told the station that the U.S. military 'did not have a good understanding of what was going on because it was a CIA mission.' In Kabul, U.S. Defence Secretary Leon Panetta did not deny that it had been spying on Iran and said the drone programme carried out 'important intelligence operations which we will continue to pursue.' The RQ-170 Sentinel is one of the United States' most sophisticated spy planes and flies at up to 50,000 feet. It is designed to evade sophisticated air defenses.  One former intelligence official told CNN that it's 'impossible to see' and discounted Iranian claims that it had been brought down by some form of electronic counter-measures. 'It simply fell into their laps,' he said - after satellite communication was lost. Iranian officials have said the drone came down over eastern Iran, hundreds of miles from the cluster of nuclear sites in the central and north-west of the country. Graphic: The RQ-170 was reportedly used to watch former Al Qaeda leader Osama Bin Laden during the Navy SEAL mission that killed him . They believe they can 'mass produce' the captured drone by 'reverse engineering' the aircraft. Meanwhile, Iranian member of parliament has . hit back at former U.S. vice president Dick Cheney, who said President . Obama should have ordered an airstrike into Iran to destroy the drone . and deny Iranians access to its technology. Kazem . Jalali told ISNA, Iran's state media agency: 'The Islamic Republic of . Iran… can give a crushing response and cut off hands of anyone who wants . to violate its air, navy and land borders.' Cheney said the Iranians will likely 'send (the drone) back in pieces after they've gotten all the intelligence they can out of it.' Panetta said he did not believe Iran would agree to the U.S. request for the drone's return but told Fox News that the stealth missions along the Iran-Afghan border would 'absolutely' continue. He added: 'Our request for return of the drone is an appropriate request,' Panetta said. 'I don't expect that will happen, but I think it's important to make that request.'
Wrong colour and wrong welding on wing joints .
We hacked into GPS system to bring it down, says Iran .
Drone was looking for nuclear sites, CNN told .
By . Craig Mackenzie . Last updated at 2:42 PM on 16th December 2011 . The unmanned U.S. spy plane captured by Iran appears to be a fake, a former Pentagon official has claimed. It is the wrong colour and  the welding along the wing . joints does not appear to conform to the stealth design that helps it . avoid radar detection, he said. But U.S. military officials have told CNN the drone was on a surveillance mission of suspected nuclear sites in the country. Scroll down for video . Drone or fake? Iranian military officials examine the craft after putting it on display . Iran's Islamic Revolutionary Guard Corps flaunted video footage of a downed plane which they claim had 'violated their air space.' on December 4th. They said it was a U.S. bat-winged RQ-170 Sentinel and boasted they guided it down electronically by hacking into its GPS system. But the ex-Pentagon worker, who does not wish to be named, questioned why the landing gear was covered up when displayed by the Iranian military. The drone's underside is obscured with banners that read: 'We'll trample America underfoot' and 'The U.S. cannot do a damn thing.' On Wednesday, state TV reported that data was still be recovered by Iranian engineers from the Sentinel, which is regularly used in stealth missions. The day before, another U.S. drone, the MQ-9, . reportedly crashed at Seychelles International Airport on the island of . Mahe after developing engine problems. Captured: Iran says it will not return the RQ-170 Sentinel reconnaissance drone that crashed in Iran this week . According to the Christian Science Monitor, Iranian scientists guided the RQ-170 to ground by 'spoofing' its GPS coordinates - tricking the plane into landing in Iranian territory instead of where it was programmed to touch down. An article in the Christian Science Monitor quoted an unnamed Iranian engineer who claimed he had been studying the inner workings of the captured RQ-170 Sentinel. He said the 'spoofing' technique made the craft 'land on its own where we wanted it to, without having to crack the remote-control signals and communications' from the U.S. control centre. Monitor writer Scott Peterson and an Iranian journalist publishing under the pen name Payam Faramarzi said the GPS weakness of aircraft has long been known to U.S. military officials. They cited a 2003 report titled GPS Spoofing Countermeasures that appears to warn of the type of attack claimed by the Iranian engineer. 'A more pernicious attack involves feeding the GPS receiver fake GPS signals so that it believes it is located somewhere in space and time that it is not,” says the report. 'This attack is more elegant than jamming because it is surreptitious.' The drone is used for covert surveillance such as the operation to spy on the Pakistan compound of Osama bin Laden before he was killed in a U.S. raid in May. U.S. officials have blamed the loss of the sophisticated spy plane on a malfunction, but have yet to explain how it was in such pristine condition after its recovery by the Iranians. U.S. and NATO officials have said it was on a mission to patrol the Afghan-Iran border and had veered off course when it went missing. Now military officials have told CNN that the Afghan government was unaware of the use of its territory to fly surveillance drones over Iran. The CIA had not informed the Defense Department of the drone's mission when reports first emerged that it had crashed. One official told the station that the U.S. military 'did not have a good understanding of what was going on because it was a CIA mission.' In Kabul, U.S. Defence Secretary Leon Panetta did not deny that it had been spying on Iran and said the drone programme carried out 'important intelligence operations which we will continue to pursue.' The RQ-170 Sentinel is one of the United States' most sophisticated spy planes and flies at up to 50,000 feet. It is designed to evade sophisticated air defenses.  One former intelligence official told CNN that it's 'impossible to see' and discounted Iranian claims that it had been brought down by some form of electronic counter-measures. 'It simply fell into their laps,' he said - after satellite communication was lost. Iranian officials have said the drone came down over eastern Iran, hundreds of miles from the cluster of nuclear sites in the central and north-west of the country. Graphic: The RQ-170 was reportedly used to watch former Al Qaeda leader Osama Bin Laden during the Navy SEAL mission that killed him . They believe they can 'mass produce' the captured drone by 'reverse engineering' the aircraft. Meanwhile, Iranian member of parliament has . hit back at former U.S. vice president Dick Cheney, who said President . Obama should have ordered an airstrike into Iran to destroy the drone . and deny Iranians access to its technology. Kazem . Jalali told ISNA, Iran's state media agency: 'The Islamic Republic of . Iran… can give a crushing response and cut off hands of anyone who wants . to violate its air, navy and land borders.' Cheney said the Iranians will likely 'send (the drone) back in pieces after they've gotten all the intelligence they can out of it.' Panetta said he did not believe Iran would agree to the U.S. request for the drone's return but told Fox News that the stealth missions along the Iran-Afghan border would 'absolutely' continue. He added: 'Our request for return of the drone is an appropriate request,' Panetta said. 'I don't expect that will happen, but I think it's important to make that request.'
colour and  the welding along the wing . joints nuclear sites in the country. Scroll down for electronically by hacking into its GPS system. have said it was on a mission to patrol the