Iran said Sunday it would not will not return a US surveillance drone that it says its armed forces captured, according to US news reports quoting a senior commander of the country's elite Revolutionary Guard.

"No nation welcomes other countries' spy drones in its territory, and no one sends back the spying equipment and its information back to the country of origin," said Gen. Hossein Salami, deputy commander of the Armed Forces, according to the semi-official Fars news agency, cited by CNN.

"It makes no difference where this drone originated and which group or country sent it to invade our air space," Salami said. "This was an act of invasion and belligerence."

Salami, speaking on state TV, warned of a "bigger" response, though he did not elaborate on what Tehran might do, according to The Associated Press.

"No one returns the symbol of aggression to the party that sought secret and vital intelligence related to the national security of a country," Salami said.

US officials have not confirmed that the drone pictured in a video released Thursday is an unmanned American stealth plane, but Pentagon spokesman George Little said that an American drone was missing, CNN reported.

Iranian state media said that the spy plane was detected over the eastern town of Kashmar, about 140 miles from the border with Afghanistan.

Iranian television broadcast video Thursday of Iranian military officials inspecting what it identified as the RQ-170 Sentinel drone.

Salami called the plane "very valuable for us" and its downing "a victory for us and a defeat for our enemies," the official Islamic Republic News Agency reported.

The news service ran several stories on the capture, under the headlines "MP: Downing of US spy drone a chance to improve local technology" and "Official: Iran among few countries possessing drone technology."

"Iran is among the few countries that possesses the most modern technology in the field of pilotless drones. The technology gap between Iran and the U.S. is not much," Salami is quoted as saying said.