Hundreds of people have gathered for the funeral of a criminal once dubbed Salford's Mr Big.
Security boss Paul Massey, 55, was shot by a masked gunman at his home in Clifton, Salford, last month.
Supt Mark Kenny, of Greater Manchester Police (GMP), urged criminal gangs "not take action into their own hands".
He said uniformed officers were not at the funeral, but armed response teams were on standby.
Mr Massey was sentenced to 14 years for stabbing a man in the groin outside a nightclub in 1999.
They stopped the traffic on a busy road in Salford to allow a funeral cortege to pass by.
A pipe band played and crowds lining the street applauded as the white, horse-drawn carriage came into view.
But they weren't here to say farewell to a local dignitary or celebrity.
This was the funeral of Paul Massey, once dubbed the Mr Big of Salford's criminal underworld.
He'd served time for stabbing a man in 1999.
In recent years the 55-year-old had attempted to rebrand himself as a businessman and politician - standing for mayor of Salford in 2015.
He was shot dead outside his home last month - bringing to fruition his own prophecy, made years earlier, that one day he would fall to a bullet.
The search for his killer continues.
"Do not take action into your own hands," said Mr Kenny in a BBC interview, appealing directly to criminals.
"Speak to the police, speak to us.
"I very much hope it is a family day and it is very much about respect for the family.
"If anything did happen we will respond appropriately and deal with it."
He said, contrary to some reports, that Mr Massey was "absolutely not" a mediator for police.
Mr Kenny denied Salford was "a lawless city" and "at the heart of it there is a really good community".
But he acknowledged there were "areas of deprivation and individuals who sometimes come together and cause serious crime".
Mr Kenny said although there were 19 gangs in Salford, "clearly they are a minority in Salford engaged in criminality."
GMP officers have targeted gangs in the city and since January have made 100 arrests and have eight money-laundering investigations.
They have also seized 26 firearms, more than £9m of drugs money and large amounts of ammunition.
Mr Massey was given the title Mr Big by the late Salford councillor Joe Burrows at a meeting to discuss civil disturbances in 1992 - which he always denied having anything to do with.
In 2012, he was unsuccessful in his mayoral bid, polling 1,995 votes - 4.45% of the poll - and coming seventh out of 10 candidates.