Defence minister demands apology from Washington for invading Iranian airspace and says plane is now its property

Iran has rejected US calls for the return of a spy drone captured by its military and instead demanded an apology from Washington.

Tehran last week identified the drone as an RQ-170 Sentinel and said it was captured over the east of the country. The almost-intact aircraft was displayed on state TV and heralded as a victory for Iran in its protracted intelligence and technological battle with the US.

Iran's defence minister, Brigadier General Ahmad Vahidi, said: "Their plane invaded Iran and Iranian forces reacted powerfully. Now, instead of offering an apology to the Iranian nation, they impudently ask for the return of the plane."

US officials say the unmanned aircraft malfunctioned and was not brought down by Iran.

President Barack Obama said on Monday the US wanted the surveillance aircraft back and has delivered a formal request for its return, though Iran is not expected to comply.

But Vahidi said the US should instead apologise for invading Iranian airspace. "Iran will defend its stance and interests strongly," he added in remarks carried by the semi-official Mehr news agency.

Hours after Obama's request, the Iranian president, Mahmoud Ahmadinejad, reiterated his minister's comments. "The Americans have perhaps decided to give us this spy plane," he said in an interview broadcast live on Monday night on Venezuelan state television. "We now have control of this plane."

On Tuesday the Iranian legislator Hamid Rasaei told an open session of parliament the drone would remain in Iran, describing it as "war booty". Later, 186 legislators in the 290-seat assembly issued a statement condemning the "invasion" and urging the international community to take a tough stance over the "dangerous act".

Meanwhile, Iranian media said Obama's plea for the drone's return put the US in the role of a "beggar".

There are concerns in Washington that the Iranians may attempt to reverse-engineer the chemical composition of the drone's radar-deflecting paint or the aircraft's sophisticated optics technology that allows operators to identify suspected terrorists from tens of thousands of feet in the air.

There are also fears that the drone's database could be hacked, although it is not clear whether any data could be retrieved – some surveillance technologies allow video to stream through to operators on the ground but do not store much collected data, but if they do, it is encrypted.

Another legislator, Parviz Sorouri, claimed on Monday that Iranian experts were in the final stages of recovering data from the captured drone.