Iran said its naval forces on Sunday detected an unauthorized entry by a U.S. Navy "spy plane" into the country's airspace and warned off the aircraft, the semi-official Tasnim news agency reported.After receiving the Iranian naval forces' warning, the U.S. Navy's EP-3E aircraft, flying above the Sea of Oman, left the country's airspace and returned to international air routes, Tasnim quoted the public relations department of the Iranian Army's Navy as saying.There was no immediate comment from the United States.The Lockheed EP-3 is an electronic signals reconnaissance variant of the P-3 Orion, operated by the U.S. Navy.Iran said its naval forces on Sunday detected an unauthorized entry by a U.S. Navy "spy plane" into the country's airspace and warned off the aircraft, the semi-official Tasnim news agency reported.After receiving the Iranian naval forces' warning, the U.S. Navy's EP-3E aircraft, flying above the Sea of Oman, left the country's airspace and returned to international air routes, Tasnim quoted the public relations department of the Iranian Army's Navy as saying.There was no immediate comment from the United States.The Lockheed EP-3 is an electronic signals reconnaissance variant of the P-3 Orion, operated by the U.S. Navy.