This is the horrifying moment a woman viciously attacks a schoolgirl after a heated argument on a bus.

The woman was caught on camera repeatedly punching the teenager in the face following a row with a group of schoolchildren on the number 88 Stagecoach service in Sheffield city centre.

Screams were heard as the woman knocked her victim to the pavement and rained down blows in front of several witnesses.

The woman was caught on camera repeatedly punching the teenager in the face following a row with a group of schoolchildren on the number 88 Stagecoach service in Sheffield city centre

Screams were heard as the woman knocked her victim to the pavement and rained down blows in front of several witnesses

The woman's partner was also seen shoving and verbally abusing children as he stopped them from trying to stop the attack.

It is not clear what sparked the initial clash, but a woman claiming to be the victim's sister said the children confronted the woman after she racially abused a passenger.

She claims her sister suffered a black eye and a suspected broken cheekbone in the assault and says she has given a statement to the police.

Footage of the attack - filmed by an onlooker - was shared on social media last night.

It shows a group of schoolchildren confronting a woman - wearing a red coat - and her partner near the doorway of the bus.

The woman's partner was also seen shoving and verbally abusing children as he stopped them from trying to stop the attack

It is not clear what sparked the initial clash, but a woman claiming to be the victim's sister said the children confronted the woman after she racially abused a passenger

Much of the argument is inaudible but at one point the woman appears to hold out her hand and shout 'back up'.

As the row escalates, she suddenly launches herself at a schoolgirl wearing a hijab and starts throwing punches.

Witnesses scream 'stop' as she shoves her off the bus and grabs hold of her before repeatedly punching the victim in the head.

Her partner, wearing a cap, pushes away children who try to intervene and says: 'Get the f*** away.'

The woman claims her sister suffered a black eye and a suspected broken cheekbone in the assault and says she has given a statement to the police

The pair eventually walk away as friends of the victim can still be heard screaming in the background

The woman bundles the victim to the ground and pummels her as passing cars blast their horns.

In tears, one witness shouts: 'She's a f****** child.' But her partner responds by hurling foul-mouthed abuse at the children and threatening them.

The woman then squares up to another onlooker and her partner has to step in to hold her back.

The pair eventually walk away as friends of the victim can still be heard screaming in the background.

A woman claiming to be the victim's sister wrote on Facebook this morning: 'My sister is the one who was attacked.

We were in A&E all night, she has a black eye and scratches on her face and neck. She needs to go back for another check as the doctors think she may have a fractured eye socket.

'All the children were traumatised when we got there but they're doing okay now.'

A South Yorkshire Police spokesman said: 'Police were called at 4.05pm on Wednesday December 4 to the Nursery Tavern on Ecclesall Road, Sheffield, following reports of racial abuse.

'A man and a woman were asked to leave the premises.

'A short time later, at 4.30pm, a further report was received of an altercation on a bus travelling along Ecclesall Road towards the city centre between the same man and woman and other individuals on the bus.

'All parties reportedly got off the bus on Ecclesall Road, where a 14-year-old girl was assaulted. The victim suffered minor injuries.

'A 40-year-old woman and a 44-year-old man, both from Sheffield, were arrested at the scene on suspicion of racially aggravated assault and public order offences.

'The incident remains under investigation.'