Police officers have been accused of being “heavy-handed” after large groups of children and teenagers were stopped from attending a city’s Christmas market and allegedly “forced” back on to trains.

Video footage shared online showed screaming youths being ushered through Manchester Victoria on Saturday after being met by a large number of Greater Manchester Police (GMP) officers.

Equality group, The Traveller Movement, said the “shocking” incident involved children from the traveller community and it was “completely unacceptable”.

GMP said the force’s priority was “always to protect public safety by preventing incidents of violence and disorder”.

Police put in place a 48-hour dispersal notice from about 12:15 GMT on Saturday after reports of anti-social behaviour on trains and in the city.

The Traveller Movement said officers had “blocked Romani Gypsies and Irish Traveller children from attending the Christmas markets”.

“This heavy-handed and discriminatory action has left children upset and distressed, with parents deeply concerned about the treatment that their children have faced,” a spokesman added.

He said: “We have been contacted by numerous parents and received video footage of Romani Gypsy and Irish Traveller children arriving into Manchester, and then being forced on to a different train and prevented from leaving the station by police.

“These children were simply trying to enjoy the festivities like everyone else, but instead have been unfairly targeted and marginalised.”

Greater Manchester’s deputy mayor Kate Green has called for an investigation into the footage.

She said: “I have watched the videos circulating on social media with concern and have asked GMP for a full report on the action taken.

“While we will not tolerate lawlessness and anti-social behaviour in Greater Manchester, I want to reassure the community that I expect the police to treat everyone fairly and with respect and I will be inviting community leaders to meet me to discuss what has happened.”

Assistant Chief Constable Rick Jackson said the force had been given “intelligence” about anti-social behaviour by groups on trains on the way into Manchester and similar reports around the city centre so a dispersal order was issued.

“This included plans for officers to re-route arriving groups back home,” he said.

“Our priority is always to protect public safety by preventing incidents of violence and disorder.”

Shortly after, officers responded to several disturbances in the city centre and intervened in altercations between groups, he said.

“We understand there are feelings of mistreatment and confusion amongst groups of people for being turned away yesterday,” Mr Jackson said.

“We are determined to address these concerns by working closely with the mayor’s office to engage these communities in Manchester and further afield.”