A murder investigation is under way after a man was stabbed to death in south London.

Scotland Yard said officers were called to Upper Green East in Mitcham at 3.29am.

Paramedics from the London Ambulance Service tried to save the victim, who is believed to be in his 20s, but he died at the scene.

A 44-year-old man is in custody after being arrested at the scene on suspicion of murder.

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Formal identification of the victim is yet to take place, police said. A post-mortem examination will be carried out.

London mayor Sadiq Khan said his "thoughts are with the victim's family".

"The homicide team is investigating and they will do everything they can to bring the perpetrator to justice," Mr Khan said.

He said he had been in touch with the police, the local MP and local council leader.

In another update, the Met Police said a 16-year-old boy had been charged with the murder of a 20-year-old man stabbed to death in Ruislip, west London.

Osman Shidane, 20, died on Friday after being found with stab injuries in Victoria Road in the town, just after 9pm on Tuesday.

Following a post-mortem on Saturday, multiple stab wounds was given as the cause of death.

The accused teenager, from Hillingdon, will appear before magistrates on Monday.

A 15-year-old girl, arrested on suspicion of assisting an offender, has been released on police bail.

:: Anyone who witnessed or has information about the Mitcham incident should call police on 020 8721 4205, or Crimestoppers, anonymously, on 020 8721 4205.