PHOENIX — Red colored lights that formed a square and then a triangle were seen floating over north Phoenix late Monday, a sight reminiscent of an unexplained 1997 sighting that has become part of the area's lore.

There was no immediate word where they came from.

The Air Force said the lights weren't from any of their flight operations and officials at Deer Valley airport and Phoenix Sky Harbor International Airport could not explain it.

The lights were visible for about 13 minutes around 8 p.m. Monday.

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A Luke Air Force Base official said the base wasn't flying any aircraft in the sky Monday night and that the lights are not part of any Air Force activities.

KSAZ-TV, a local Fox affiliate in Phoenix, reported that officials from Phoenix Deer Valley Airport saw the lights approximately 4 miles south of the airport and that the lights were rising as they watched.

Airport officials said the lights were not from any aircraft at that airport.