Two teenagers were killed and three others were stabbed during a 12-hour spree of violence in London.
Fourteen people have been connected to the incidents in Wandsworth, Plumstead and Clapham.
London mayor Sadiq Khan said he was "sickened" following the deaths of the two teenage boys in Wandsworth and Plumstead.
Metropolitan Police were called to Wandsworth, south-west London, at 4.42pm last night where the victim, believed to be in his late teens, was found stabbed.
He is yet to be formally identified.
Six males were taken to a west London police station for questioning.
A few minutes later at 4.54pm, armed police were called to Plumstead following reports of a shooting.
The victim, also in his late teens, was found with critical injuries and died at the scene.
Three men and a woman were arrested on suspicion of murder.
Then at 3.22am on Saturday, police were called in Clapham. Three men were found with stab and slash injuries.
The condition of two of the men remains unknown. The third has injuries which are described as not life-threatening or life changing.
A source told ITV News that a cordon will remain in place around Clapham High Street until they know if the attack is fatal.
Four men have been arrested in connection to the incident.
Sadiq Khan has urged that “Anybody who has information about what happened either in Wandsworth or Greenwich should do the right thing and call the police.”
Photo: Police have cordoned off the scene around Clapham North Tube station. Credit: PA
Photo: Police officers near to the scene in Deeside Road in Wandsworth Credit: Isabel Infantes/PA