DUBAI, WASHINGTON - Iran said it would deal decisively with any foreign encroachment into its airspace, an apparent warning to the United States after one of its surveillance drones was targeted by Iranian warplanes last week."The defenders of the Islamic Republic will respond decisively to any form of encroachment by air, sea or on the ground," Fars news agency quoted General Massoud Jazayeri, a senior armed forces commander, as saying on Friday. "If any foreign aircraft attempts to enter our airspace our armed forces will deal with them," he said. Jazayeri did not mention the drone incident specifically.Pentagon officials said the unarmed drone was in international airspace when Iranian warplanes opened fire on it on Nov. 1 but the aircraft was not hit. Washington has issued a formal protest to the Iranian authorities.The Nov. 1 intercept was the first time Tehran had fired at an unmanned American aircraft, in a stark reminder of how tensions between the United States and Iran could escalate quickly into violence.If Iran had hit the drone, as the Pentagon believes it was trying to do, it could have forced American retaliation - with the potential consequences that entails.According to the timeline provided by the Pentagon, two Iranian SU-25 "Frogfoot" aircraft intercepted the American drone at about 4:50 a.m. EST (0850 GMT) as it conducted a routine, but classified, surveillance mission over Gulf waters about 16 nautical miles off the Iranian coast.Pentagon spokesman George Little said the aircraft fired multiple rounds at the Predator drone and followed it for at least several miles as it moved farther away from Iranian airspace."We believe that they fired at least twice and made at least two passes," he said.International airspace begins after 12 nautical miles and Little said the drone at no point entered Iranian airspace. Last year, a crashed CIA drone was recovered inside Iran.Defense Secretary Leon Panetta was quickly notified of the incident, as were members of Congress and the White House, Little added. The United States also sent Iran a warning through diplomatic channels, saying it would defend its military assets and would keep sending aircraft on such surveillance operations."There is absolutely no precedence for this," Little said. "This is the first time that a (drone) has been fired upon to our knowledge by Iranian aircraft."Many questions about the incident remain, including why Iranian warplanes could not manage - if they wanted - to shoot down an unarmed drone, which lacks advanced capabilities to outmaneuver them.Asked whether the Iranian aircraft were simply firing warning shots, Little said: "Our working assumption is that they fired to take it down. You'll have to ask the Iranians why they engaged in this action."