Two military planes collided in midair on Sunday afternoon during an air show at the Mountain Home Air Face Base in Idaho, according to a witness and videos shared on social media.

A video on social media showed the jets spinning toward the ground.

At least four crew members deployed their parachutes and ejected from the planes, which then exploded into balls of fire. The conditions of the crew members were not immediately available.

A witness at the scene who shared a video said the show’s announcer said the crew members were all accounted for.

“They crashed in an unpopulated area off base,” said the witness, Lindsay Dressler. She said a brush fire broke out after the crash.

The “aircraft incident” took place two miles northwest of the base, the Mountain Home Air Force Base Gunfighters said on Facebook. The base is home to the U.S. Air Force’s 366th Fighter Wing, also known as the Gunfighters.

The scene was under investigation and emergency crews were at the site. The base did not immediately provide more details.

The base, in southwestern Idaho about 50 miles south from Boise, the state capital, was locked down on Sunday afternoon.

A spokesman for the Federal Aviation Administration referred inquiries to the Mountain Home Air Force Base.

In April, the 366th Fighter Wing at the base announced the Gunfighter Skies Air Show, which began on Saturday and was scheduled to run through Sunday.

The free, public event featured the U.S. Air Force Thunderbirds, the Mountain Home Air Force Base said in a news release. “Gunfighter Skies will showcase the precision, capability and readiness of the U.S. Air Force,” the base said.

The base is home to about 8,600 people, including service members and their families.

Mountain Home Police said the show was canceled and urged people to avoid the area around the base.

Robert Robinson, 26, was driving to the event with his wife around 12:10 p.m. when the crash happened.

“All of a sudden, we saw the full profile of one of the planes,” he said. “I was like, that’s either a cool stunt or something major just happened.”

He said it took him several minutes to realize it was a collision.

“I saw the major change in flight direction, and you know, control of the aircraft being lost, and that was about the moment that I realized, oh, something was very wrong. It was surreal to say the least,” he said.