Police have arrested an 18-year-old man on suspicion of murder following the death of a man in Chapeltown on Sunday night.
Officers were called to an incident on Chapeltown Road, near the junction with Button Hill, just before 10pm and found a man seriously injured.
The man was given emergency treatment at the scene and was taken to Leeds General Infirmary by ambulance.
Sadly, he was pronounced dead in hospital a short time later.
The man is yet to be formally identified but police believe he is 21 years old.
A post mortem examination is due to take place later today to establish the cause of his death.
Police arrested a 18-year-old man on suspicion of murder at the scene, after he was found in Button Hill with serious injuries at the same time.
He was taken to hospital for treatment but his injuries are not believe to be life threatening.
A police cordon remained on Chapeltown Road on Monday morning while officers investigate the scene, diverting part of the Leeds West Indian Carnival.
Detective Superintendent Mark Swift, of West Yorkshire Police Homicide and Major Enquiry Team, said: "The investigation is at an early stage but we are treating this man’s death as murder.
“We are carrying out extensive enquiries to establish the full circumstances of this incident and would like to hear from anyone who witnessed the assault itself or the circumstances leading up to it, or who has any information that could assist us.
“The scene in Chapeltown Road has been cordoned off and is likely to remain in place for some time. It is obviously vital that it is fully and comprehensively examined for evidence but we will be doing everything we can to minimise the disruption this may cause to the local community.”
An early morning J'ouvert parade, part of the Leeds West Indian Carnival, had to be diverted along a different route to avoid the police scene.
Superintendent Nick Smart, who is leading the policing operation for the carnival, said: "The scene in Chapeltown Road has meant that the J’ouvert event this morning had to be diverted to a different route.
"We are continuing to liaise with our colleagues who are investigating the murder, our partners at the local authority and with the carnival organisers.
“We hope people will understand how important it is that this young man’s murder is properly investigated and that the scene will need to be kept in place for as long as is necessary.
“We appeal to people to work with us and be patient while we work with our partners to put suitable plans in place to accommodate the needs of this important community event alongside what is necessary for the investigation.”
Anyone with information is asked to contact the Homicide and Major Enquiry Team via 101 quoting crime reference 13190435697 or call the independent charity Crimestoppers anonymously on 0800 555 111.