A man has died and two people have been seriously injured after reports of a disturbance in west London.
Metropolitan Police officers were called to Birkbeck Road, Acton at 04:05 GMT on Sunday where officers found a man injured at the scene.
Despite the efforts of the emergency services, he died a short time later.
The London Ambulance Service (LAS) said two people were taken to major trauma centres as priorities.
Police said a number of other people were believed to have been injured nearby with some receiving treatment.
The force said a large crime scene was in place including a number of road closures.
The spokesperson added: “While we recognise the impact this will have on local residents and businesses, it is essential to provide us with the best chance to secure evidence.”
“The public can expect to see a significant police presence in the area as officers begin their investigation.”
An ambulance spokeswoman said: “We sent a number of resources to the scene, including ambulance crews, a paramedic in a fast response car and an incident response officer. We also dispatched London’s Air Ambulance.
“Sadly, despite the best efforts of our crews, one person died at the scene.
“Two patients were taken as priorities to major trauma centres.”
Police have appealed for witnesses.