A U.S. super-secret spy plane believed to be in Iranian possession could be a major loss for the U.S. military -- and a major gain for Iran.

According to a senior U.S. military source with intimate knowledge of the Sentinel drone, the aircraft likely "wandered" into Iranian air space after losing contact with its handlers and is presumed to be intact since it is programmed to fly level and find a place to land, rather than crashing.

"This is a big prize in terms of technology," a senior U.S. military source told Fox News.

The spy plane uses the same stealth technology as the drone used to monitor the compound during the raid that killed Usama bin Laden, U.S. military sources told Fox News on Monday.

Military sources confirmed that the Iranians have the RQ-170 drone, which is so advanced that the U.S. Air Force has not distributed even a photo of it. However, they did not say that the Iranians shot down the spy plane, as was reported by Iran's official IRNA news agency.

IRNA quoted an unidentified Iranian military official saying Sunday that the spy plane was shot down by Iran's armed forces and suffered minor damage.. The official also warned of strong and crushing response to any violations of the country's airspace by American drone aircraft.

Earlier, the U.S.-led coalition in Afghanistan issued a statement saying the aircraft may have been a drone that operators lost contact with last week while it was flying a mission over neighboring western Afghanistan.

A U.S. official, who spoke on condition of anonymity because of the classified nature of the incident, said the U.S. had "absolutely no indication" that the drone was shot down.

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.

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. In July, Iranian military officials showed Russian experts several U.S. drones they said were shot down in recent years.

Also in July, Iranian lawmaker Ali Aghazadeh Dafsari said Iran's Revolutionary Guard shot down an unmanned U.S. spy plane that was trying to gather information on an underground uranium enrichment site.

The RQ-170 Sentinel is made by Lockheed Martin and is equipped with stealth technology. The $6 million stealth aircraft manufactured by Lockheed Martin has an RQ in its name to indicate it is unarmed.

Neither the Air Force nor manufacturer Lockheed Martin has released much information about the plane, dubbed "The Beast of Kandahar" in 2007 when its existence was finally confirmed.

"The RQ-170 Sentinel, a low observable UAV, was built by Lockheed Martin's Advanced Development Programs," Major Cristin L. Marposon, a public affairs officer for the USAF at the Pentagon, finally told FoxNews.com in 2009.

Sources said that the plane was designed for surveillance, not for attack.

Little is known about the plane beyond its intended goals, however, with no official images released or details about its composition. Leaked photographs purportedly of the craft depict a sleek, biwing design, intended to present a stealthier, harder to hit profile that other drones or other aircraft.

"The USAF has not issued any public release photos of the RQ-170," Melissa Dalton of Lockheed Martin told FoxNews.com

Early reports suggested that plane -- which supposedly has a wingspan of about 65 feet and can fly at around 50,000 feet -- would be made almost entirely without metal to help it dodge radar, and special paint provides additional stealth.

Sen. Mark Kirk, R-Ill., told Fox News on Monday that "it's less likely than not" that the Iranians did not shoot down the plane, but it had a mechanical or computer malfunction that caused it to go down. The Iranians then used it "for propaganda purposes."

"In the past, they have claimed these shoot-downs and been unable to produce any pieces of the drone, and currently, they have not exhibited any piece of the RQ-170 yet," he said.

FoxNews.com's Jeremy A. Kaplan contributed to this report.