The U.S. Air Force said Tuesday it has concluded that pilot error caused a midair accident in October, when two F-15 fighters clipped each other off Okinawa.

It said the pilot of one of the fighters was distracted, lost control of his aircraft and crossed into the flight path of the other jet during a drill. Neither pilot was aware of any damage and continued the flight, it said.

There were no injuries in the accident.

The Foreign Ministry's Okinawa office said it has obtained a detailed report on the incident from the U.S. military.

The air force ordered the two pilots to brush up on basic flight training.

The U.S. military said earlier that the fighters, from the 12th Fighter Squadron stationed at Elmendorf Air Force Base in Alaska, inadvertently made contact in an over-water training area when the left wingtip of one aircraft clipped the vertical fins of the second.

The incident forced an emergency landing at Kadena Air Base and immediately sparked protests from local officials and residents.