LOS ANGELES, July 23 (UPI) -- The U.S. Federal Aviation Administration says it is investigating why a Delta passenger jet nearly collided with a single-engine private plane in California.

FAA spokesman Mike Fergus said the two-engine Boeing 737 Delta jetliner, which was on approach to Los Angeles International Airport at 11,900 feet Tuesday, came within seventh-tenths of a mile of a four-seat private plane en route to Arizona, the Riverside (Calif.) Press-Enterprise reported Wednesday.

Fergus said the pilot of the private plane said he had made a wrong turn before the near-collision in the vicinity of Ontario, Calif.

"It was way too close," Fergus said. "It was a very serious situation."