Iran made a formal protest on Thursday over a US drone entering "deep" into its eastern airspace last week, and aired footage of what appeared to be the downed aircraft on state television.

Swiss ambassador Livia Leu Agosti was summoned to the foreign ministry and told the incident suggests Washington has upped its "provocative and covert actions" against the Islamic regime, the state television website reported.

The Swiss embassy handles US interests in the absence of Iran-US diplomatic ties.

Iran "strongly protests the violation of an RQ-170 spy aircraft deep into its airspace," the report said, adding that Tehran asked for "an urgent response and compensation from the US government."

It did not elaborate.

Iranian media said late Sunday an RQ-170 unmanned aerial vehicle was shot down after making an incursion slightly into Iranian airspace. But no precise indication has been given by Iranian officials on where it crashed.

US media said the drone crashed in eastern Iran probably due to malfunction.

The RQ-170 Sentinel is a high-altitude stealth reconnaissance drone made by Lockheed Martin, whose existence was exposed in 2009 by specialised reviews and later confirmed by the US Air Force in 2010.

On Thursday, Iran's foreign ministry said in a written complaint passed on to the Swiss ambassador that it holds "the US government fully responsible for this action, which is against all known international laws and regulations."

Iran's state television aired Thursday evening footage of what it said was the captured drone, showing what appeared to be an RQ-170 Sentinel in good shape and with little visible damage.

The footage showed a cream-coloured aircraft being examined by two commanders of the elite Revolutionary Guard, who are in charge of the country's air defences.

One of them, Brigadier General Amir-Ali Hajizadeh who heads the Guards' aerospace unit, claimed the drone had been captured through a cyber attack.

"It fell into the trap of (the Guards) electronic warfare unit who then managed to land it with minimum damage," Hajizadeh said.

The RQ-170, he said, is about 26 metres (85 feet) in wingspan, 4.5 metres (15 feet) in length and 1.84 metres (6 feet) in height.

He also said Iranian experts were "well aware of what priceless technological information" could be gathered from the aircraft, without elaborating.

US media have reported fears in the United States that Iran could access and make use of highly-advanced technology found in the drone.

But a US official, who declined to be named, said on Wednesday that the United States had doubts "the Iranians have the expertise" to exploit the technology found in the wrecked vehicle.

According to US media reports Thursday, revelations about the US stealth drone suggest Washington is stepping up surveillance and pressure on the Islamic republic over its nuclear programme.

The New York Times reported that the drone was part of a surveillance programme that has frequently sent the hard-to-detect aircraft into Iran to map suspected nuclear sites.

The crash came at a time of heightened political tension over Iran's nuclear programme, with speculation rife that Israel is mulling air strikes against Iranian atomic facilities, with or without US backing.