Iran said Monday that a copy of an American drone downed over its territory in 2011 had successfully completed its first test flight, promising to release footage of the experiment.

Tehran captured the US RQ-170 Sentinel in December 2011 while it was in its airspace, apparently on a mission to spy on the country's nuclear sites, media in the United States reported.

Iran said it had taken control of the ultra hi-tech drone and forced it down in the desert where it was recovered nearly intact.

Washington says the drone crashed after experiencing a technical glitch.

In May, a military official said Iranian engineers had successfully built a replica of the American drone and that it would soon take a test flight.

Images broadcast by state television at the time appeared to show two near-identical drones.

"As promised, we have conducted the flight and a film of it will be broadcast shortly," General Amir-Ali Hadjizadeh, commander of the Revolutionary Guards air wing, was quoted as saying by the corps' own website.

Apart from a fast-moving ballistic weapons programme, Iran has been producing drones since 2010 which the defence ministry says are capable of firing missiles with a range of 1,000 kilometres (more than 600 miles).

Tehran says its weapons programmes are purely for defensive purposes, but the United States whose Fifth Fleet is based in Bahrain across the Gulf has often voiced concerns.