Image copyrightCHICAGO POLICE

Four black people face hate crime and kidnapping charges for the Facebook Live-aired torture of a mentally disabled white man.

Jordan Hill, Brittany Covington and Tesfaye Cooper, all 18, and 24-year-old Tanishia Covington are expected to appear in a Chicago court on Friday.

In the video, the assailants can be heard making derogatory statements against white people and Donald Trump.

Chicago police have described the incident as "sickening".

Torture video prompts online race fight

Cook County prosecutors have also charged the suspects with aggravated unlawful restraint and aggravated battery with a deadly weapon.

Mr Hill is further charged with robbery and possession of a stolen motor.

All the suspects, apart from Tanishia Covington, each face an additional count of residential burglary.

White House press secretary Josh Earnest said the attack demonstrates "a level of depravity that is an outrage to a lot of Americans".

He said he has not yet spoken to Barack Obama about the incident in his hometown of Chicago, but added that he is certain the president would be angry.

Image copyrightFACEBOOK

Police said the unnamed 18-year-old victim was dropped off by his parents at a McDonald's restaurant on 31 December to meet his friend, Jordan Hill, who later became one of his attackers.

The pair drove around for two days, sleeping inside a van that Mr Hill had allegedly stolen without the victim's knowledge, before ending up at the Covington sisters' home.

Police said a play fight led to a prolonged assault in a flat on the Illinois city's west side.

The captive was made to drink from a toilet bowl, had part of his scalp removed with a knife, and was bound, gagged and beaten.

Chicago Police Commander Kevin Duffin said the victim finally escaped when his attackers went downstairs to confront a resident who had called police because of the noise.

Cdr Duffin said the racial slurs and references to the victim's mental capacity, depicted in the video, led to the hate crime charges.

One of the female attackers allegedly kicked in the front door of the neighbour's home, resulting in burglary charges for three of the suspects.

The escaped captive was found disorientated and traumatised, walking the streets in shorts and sandals with Mr Hill.

The victim, who had difficulty communicating with police, was taken to hospital for medical treatment, and discharged.

More on violence in Chicago

"I've been a cop for 28 years," said Chicago Police Superintendent Eddie Johnson earlier, "and I've seen things that you shouldn't see in a lifetime, but it still amazes me how you still see things that you just shouldn't."

In the 30-minute video, the attackers can also be seen cutting the victim's clothes, dropping cigarette ash on him and pushing his head back with a foot.

Several people can be seen drinking, laughing and smoking, while their captive cowers in the corner of the room.

In other videos posted online the young man is forced at knife-point to say: "I love black people".

An African-American woman talks to the camera, sometimes with slurred speech.

But the grandmother of one of the young women charged said her granddaughter is "a good person" who has had her "ups and downs".

Priscilla Covington said the video does not reflect the young woman she said she had raised since she was a baby.

The incident has provoked a strong reaction on Twitter, especially among the alt-right - the fringe group that celebrated US President-elect Trump's election win with Nazi salutes.