An 18-year-old man has died after a fight in which three other people were injured.
Greater Manchester Police were called to reports of a large brawl in Crosshill Road, Moss Side, just before 8.40pm on Tuesday.
Four people were taken to hospital with stab wounds, including the 18-year-old, who died shortly afterwards.
Superintendent Dave Pester, from GMP's City of Manchester team, said: "We completely understand that the community will be concerned after waking up and hearing this tragic news this morning. I want to assure you we have had officers on the ground, working solidly through the night, trying to get to the bottom of what has happened.
"We are in the very early stages of this investigation and we are trying to understand the motive behind this attack and who is responsible."
The incident comes after 11 people, including a 14-year-old boy, were convicted of murder and manslaughter following the death of 18-year-old Abdul Hafidah, who was chased and attacked by a gang in Moss Side in May last year.
The murdered teenager was reportedly a childhood friend of suicide bomber Salman Abedi, who killed 22 people when he detonated a device at the Manchester Arena on May 22.
Three men were found guilty of Mr Hafidah's murder on Tuesday following a trial at Preston Crown Court.
Police said there was no information to link Tuesday night's incident to the trial.
Mr Pester added: "At the forefront of this investigation, as always, are the victims and their families. Specially trained officers continue to offer their support and we will do everything in our power to give this young man's family the answers they deserve."
Anyone with any information should call police on 101 quoting incident number 1918 of Wednesday 9 August 2017.