The second day of a British air show has been canceled after a plane crashed and exploded into a fireball Saturday, killing at least seven people. A Hawker Hunter jet -- a historic military plane -- plummeted into a road near the Shoreham Airshow at Shoreham-by-Sea in southeastern England.

Organizers of the Royal Air Forces Association event announced via Twitter that the Sunday portion would be canceled in the wake of "today's serious incident." 

Eyewitnesses told BBC News the jet's pilot failed to complete a loop during the plane's performance.

"He'd gone up into a loop, and as he was coming out of the loop I just thought, 'You're too low, you're too low, pull up," observer Stephen Jones said, according to the media outlet. "And he flew straight into the ground either on or very close to the A27, which runs past the airport."

The South East Coast Ambulance Service confirmed via Twitter Saturday that were seven fatalities, as well as one "serious injury and 14 walking wounded."

All the casualties are "believed to have occurred on the road at this time and there are not thought to be any injuries to anyone actually on the airfield," the Sussex Police said in a statement. Sections of that road, the A27, have been closed, and the U.K.'s Air Accident Investigation Branch was on the scene, local authorities said.

About 20,000 people were in attendance at the air show Saturday, according to Sky News. A fatal crash that killed one person occurred at the same event in September 2007.