A school assistant allegedly attacked a pupil who refused to sit down on a bus in Florida.

The girl's older sister recorded the incident on a phone aboard a Northport K-8 school vehicle in Port St. Lucie on March 13 at around 4:30 pm.

Footage shows the pupil kneeling in her seat, facing the person taking the video, when bus aide Avieser Pinillos approached her.

He then grabbed her and forced her to sit down before shockingly shaking and yelling at the nine-year-old pupil, who has special needs.

Chief Leo Niemczyk of the Port St. Lucie Police Department described the behaviour as aggressive and violent.

He said: 'He clearly lost his temper, and it's completely unacceptable.'

Court documents reveal a witness stated that Avieser gave the girl one command to sit before the situation escalated physically.

The same on-scene individual noted that this was not the first incident between Avieser and the girl, though it was more severe than previous encounters.

Authorities reported that the student had red marks on her neck and shoulders but no serious injuries.

Chief Niemczyk added: 'Any reasonable adult would feel angry seeing one of our most vulnerable members of society victimised in that way.'

Avieser now faces one count of child abuse and has been removed from his position by the St. Lucie County School District. They are also considering permanently terminating him.

Police added: 'I think it would make any parent feel angry.'