UNITED NATIONS - Iran Thursday called on the United Nations to condemn a US unmanned drone's violation of its air space and sought "clear and effective measures" to end such "dangerous and unlawful acts" against the country.

Mohammad Khazaee, the Iranian permanent representative to the United Nations, made the appeal in his letter to UN Secretary-General Ban Ki-moon.

The letter was also copied to Vitaly Churkin, the Russian UN ambassador who holds the rotating UN Security Council presidency for December, and Nasser A. Al-Nasser, president of the 66th session of the UN General Assembly.

"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, " the Iranian ambassador said in the letter.

"In the continuation of such trend, recently, an American RQ-170 unmanned spy plane, bearing a specific serial number, violated Iran's air space," he said.

"This plane flied 250 kilometers deep into Iranian territory up to the northern region of the city of Tabas, where it faced prompt and forceful action by the Armed Forces of the Islamic Republic of Iran."

Iranian media reported Sunday that the Iranian military downed a RQ-170 US reconnaissance drone in eastern Iran after it had transgressed Iranian borders.

But US officials denied the drone was brought down by Iran, insisting it crashed due to mechanical difficulties.

The RQ-170 drone is an unmanned aircraft that has been used for reconnaissance and surveillance by the United States in Afghanistan.