UNITED NATIONS - The United Nations acknowledged on Friday receiving Iran's request to condemn US drone flights over its territory as "acts of aggression."

The spokesman for UN Secretary-General Ban Ki-moon, Martin Nesirky, told Xinhua that "I can confirm that a letter to the secretary-general has been received from the Iranian permanent representative (Mohammad Khazaee) ... We don't have any comment."

Ban was visiting the capital of Somalia, Mogadishu, along with the president of 66th UN General Assembly, Nasser A. Al-Nasser.

In a copy of the letter Xinhua received from the Iranian mission, Khazaee said he has sent an identical letter to Al-Nasser as well as the president of the UN Security Council for December, Russia's UN Ambassador Vitaly Churkin.

Churkin, briefing the media after council consultations on other matters on Friday afternoon did not mention receipt of the letter or any plans for the panel of 15 member states to discuss the request.

Iran reported it had downed the US unmanned stealthy aircraft on Sunday as it flew over the eastern part of the country. On Thursday it displayed on national television what it said was the aircraft, a white, bat-winged vehicle appearing, basically undamaged, in published photographs as a much smaller version of the US B2 Spirit Stealth Bomber but with its undercarriage cloaked from view by a skirt.

"Upon instructions from my government, I have the honor to draw your kind attention to the provocative and covert operations against the Islamic Republic of Iran by the United States government, which have increased and intensified in recent months, " said the Iranian ambassador in his letters Thursday to Ban, Churkin and Al-Nasser.

"In the continuation of such trend, recently an American RQ-170 unmanned spy plane, bearing a specific serial number, violated Iran's airspace," Tehran's envoy continued.

"This plane flew 250 kilometers deep into Iranian territory up to the northern region of the city of Tabas," he said.

Tabas is in central Iran nearly 1,000 kilometers southeast of the capital, Tehran.

The envoy did not say the spy craft was shot down but just that "it faced prompt and forceful action" by Iran's armed forces.

"This is not the only act of aggression and covert operation by the United States," Khazaee said, referring to similar protest notes sent to the United States in October 2008 and February 2009.

"My government emphasizes that this blatant and unprovoked air violation by the United States government is tantamount to an act of hostility against the Islamic Republic of Iran in clear contravention of international law, in particular, the basic tenets of the United Nations Charter," the letter said.

"The Iranian government expresses its strong protest over these violations and acts of aggression and warns against the destructive consequences of the recurrence of such acts," it continued. "The Islamic Republic of Iran reserves its legitimate rights to take all necessary measures to protect its national sovereignty."

"My government, hereby, calls for the condemnation of such acts of aggression and requests for clear and effective measures to be taken to put an end to these dangerous and unlawful acts in line with the United Nations' responsibilities to maintain international and regional peace and security, in accordance with the letter and spirit of the United Nations Charter," the letter said.

The US Mission to the United Nations was asked for comment on the letter to Ban from Khazaee, but there was no immediate response.

The New York Times reported on Friday US officials viewing the video of the aircraft refused to confirm or deny that it was the one they said was lost by controllers in Afghanistan.

The United States had said it lost control because of a malfunction.

The Times said the aircraft depicted in the video appeared to be in good condition except a close inspection showed what appeared to be tape on a wing, possibly concealing some damage, such as a fracture.

The United States, while not always in the forefront, has been actively against Iran's nuclear program along with its Western European allies. Tehran has long insisted it is strictly for peaceful purposes.

The US spy-in-the-sky down in Iran this week had been looking out for nuclear activity in Iran, rather than monitoring military activity in adjacent Afghanistan, Tehran has said.