(Reuters) - Popping balloons during a fire inspection at a Florida mall panicked shoppers who mistook them for gunfire, triggering a stampede in which nine people were hurt, authorities said on Friday.

The false alarm at Orlando's Florida Mall occurred on Thursday during the inspection of a fire-suppression system at a restaurant being opened by 'NSync singer Joey Fatone, the Orange County Sheriff's Office said in a statement.

The inspection included the bursting of six large balloons in a row, an industry-standard test, followed by a fire alarm, the statement said.

"People mistook it for gunfire, so people started fleeing," said Orange County Fire Rescue spokeswoman Ngoc Huynh.

Four of the nine people injured in the panic were transported to hospitals, she said.

A contractor was carrying out the inspection with a fire marshal on scene. The sheriff's office said an announcement had been made about the test on the mall's public address system.

Orlando is the site of the June shooting at the Pulse gay nightclub, where 49 people were killed and 53 were wounded.

(Reporting by Ian Simpson in Washington; Editing by Lisa Von Ahn)