Chicago police are questioning four people over a video in which a disabled teenager appears to be tied up and tortured while someone yells “f*** Donald Trump” and “f*** white people”.

Captured in a broadcast on Facebook Live, the footage shows a young white man sitting in the corner of a room with tape over his mouth.

It shows a large knife being held to his face and his scalp being cut, before he is kicked repeatedly and forced to drink toilet water.

The victim is clearly forced to drink toilet water in the Facebook Live video Fox 32 (Fox 32)

The group are shown taunting and swearing at the victim, while large parts of the footage focus on a woman rambling incoherently.

While police officials did not confirm the races of the suspects or victim, video from Chicago media outlets appeared to show someone off-camera using profanities about "white people" and President-elect Mr Trump.

Police superintendent Eddie Johnson said criminal charges against the four people arrested, two men and two women, were expected to be announced on Thursday.

“It’s sickening," he said.

“You know it makes you wonder what would make individuals treat somebody like that.”

He said the victim, who has "mental health challenges," was recovering.

Police said it was too soon to know whether the attack was racially motivated.

Detectives say the victim met acquaintances in the northwest Streamwood suburb, before he was driven to Chicago in a stolen vehicle.

The victim, thought to be 18 years old, is believed to have been held hostage for at least 24 hours in an apartment.

On Tuesday, the same day the 30-minute video was uploaded by a woman, police say they spotted the victim walking on a West Side street in a state of distress.

Although the President-elect is mentioned, Chicago police say they are not treating it as politically motivated.

Chicago Police Commander Kevin Duffin said: “It’s quite a possibility that this is a kidnapping and that’s certainly one of the charges we’ll be seeking if it turns out to be that.

“But, he’s traumatised by the incident and it’s tough to communicate with him at this point.”

Supt Johnson said: “I think some of it is just stupidity, people just ranting about something that they think might make a headline.

Police Supt Eddie Johnson implied the attack was not politically motivated and referred to the Donald Trump insults as 'stupidity' Fox 32/screengrab (Fox 32)

"I don't think that at this point we have anything concrete to really point us in that direction, but we'll keep investigating and we'll let the facts guide us on how this concludes.

“Images in the video put on display the brazenness of the offenders who assaulted the victim and then broadcast it for the entire world to see."