The sonic boom over Tucson that rattled windows and nerves Wednesday night was caused by a fighter jet that broke the sound barrier while training in the desert west of the city, officials said.

The 425th Fighter Squadron from Luke Air Force Base in Glendale was on a training mission in F-16 jets when one of the aircraft broke the sound barrier west of Kitt Peak, said Staff Sgt. Chris Hatch, a spokesman for the 56th Fighter Wing at Luke.

Hatch said the pilot was allowed to break the sound barrier as part of the training. He could not say if similar training was planned soon.

Reports of the window-rattling boom flooded social media sites, and hundreds of calls came in to Tucson area 911 dispatchers at about 7:45 p.m. Wednesday.

The Pinal County Sheriff’s Office didn’t report any calls from concerned residents. But the Pima Sheriff’s department heard from people living West of Campbell Avenue and as far north as the Pinal County line and as far south as Green Valley, spokesman, Deputy Tom Peine, said.

The Tucson Police Department contacted Davis-Monthan Air Force Base, Tucson International Airport and the National Guard, said department spokesman Sgt. Chris Widmer, “but they didn’t know the cause of the noise.”

It wasn't until late Thursday afternoon that Luke ended Tucsonan's speculation about the mystery noise.

Senior Editor, News, Arizona Daily Star, Tucson, Az.