DETROIT -

One day after a passenger on a Detroit DDOT bus said she was slapped by a driver, the bus drivers union said the driver was defending himself from an assault.

Jeanne Dorado, who recently moved to Detroit from Minneapolis, said her first trip on a DDOT bus was a nightmare.  Dorado said the driver, identified as Charles Kimball, threatened her and refused to let her get off the bus. Dorado said Kimball then slapped her.

Read back: Woman says Detroit bus driver 'snapped,' attacked her on bus

"He got up from his seat, the bus was still in motion, then he backhanded me with his right hand, across my face and up my head," Dorado said.

Other passengers on the bus backed up Dorado's story.  But Fred Westbrook, the president of the bus driver's union, said the story was quite different.

"Mr. Kimball was assaulted and all he did was protected himself. He had to push a passenger off him and that's what he had to do," Westbrook said.

Fred Westbrook added that DDOT drivers are often the target of unruly passengers.

"So they take their frustrations out on us and they think we're punching bags. We're not going to continue to be punching bags. We're going to get up and we're going to defend ourselves," Westbrook said.

As many as four 911 calls were reportedly made from the bus at the time of the incident. The Detroit police department is investigating.

Jeanne Dorado said she will no longer ride DDOT buses.

"It's a circus. It's out of control," Dorado said.