Two US fighter jets have collided at an air show in the state of Idaho, according to local media reports.

The crash involving two E/A-18G Vikings Growler demo team aircraft occurred during a performance at the Gunfighters Air Show at Mountain Home Air Force Base.

An announcer told the crowd shortly after the crash that all four US Navy pilots were "found safe," with video taken by spectators showing the collision of both jets and four parachutes in the air in the aftermath of the crash.

"We had four good parachutes," said the air show announcer.

"The crews were able to eject. They’re located one mile south of where the smoke is. The parachutes came down."

Officials classified the incident as a "mid-air collision," and the Air Force base has been placed on lockdown as an investigation is underway.

This is the first time in eight years that the air show has been held at Mountain Home Air Force Base.

Previous accidents occurred at the event, according to the Idaho Statesman newspaper.

A hang glider pilot died in an accident at the 2018 air show.

In 2003, an Air Force Thunderbird jet crashed, but the pilot was able to eject safely.

Due to Sunday's crash and the subsequent investigation, the remaining air show events have been cancelled.