TEHRAN -- Tehran has officially filed a complaint to the United Nations to sue Washington over the recent "violation" of its airspace by a US drone, an Iranian official said Friday.

"The complaint was filed to the UN Security Council over the violation of our airspace by the US drone," Gholam-Hossein Dehqani, deputy Foreign Minister for Legal and International Affairs, was quoted by official IRNA news agency as saying.

Iran reserves the right to respond "firmly" if the Unite States repeats the violation of the country's airspace, according to the text of the complaint.

On June 20, Iran's Islamic Revolution Guards Corps (IRGC) downed a US "spy" drone in Iran's southern province of Hormozgan.

IRGC claimed that the aircraft had violated Iran's airspace, which the United States denied.