The victims were 14 suspected attackers and a police officer. The death toll for the gang uprising that began last Friday now stands at 170.
Brazilian police pressed on with counter-attacks against the powerful Sao Paulo gang First Capital Command that is blamed for starting the street war.
However, the gang appears undeterred and continued its rampage, burning eight buses and firing at police stations.
First Capital Command leader Marcos Camacho, in a telephone interview from jail with a television network, warned that his gang could step up its offensive.
"We are ready for much more, we have the means for much more," Marcos Camacho said in an interview with Bandeirantes. Authorities questioned the interview's authenticity.
Camacho, also known as Marcola, took responsibility for the violent campaign, which the gang launched last Friday in retaliation for the transfer of hundreds of inmates to a maximum security prison. Some 40 police officers have been killed.
The gang boss said he has tried to find a way to end the bloodshed, but that police "do not want to" and have "declared war."
Innocents killed
The state government said Bandeirantes should prove the interview's authenticity. A state spokesman said authorities were sure Camacho had no access to a telephone.
Human rights groups have expressed concern about the police counter-offensive, citing press reports of officers killing innocent people. Police had yet to release the names of suspects it had killed.
"There are death squads with masked people who come out of cars or motorcycles and kill people," said Ariel de Castro Alves, coordinator of the National Human Rights Movement.
"We already have a list of 16 people who were killed and had nothing to do with crime," Mr Castro Alves said. The state police's watchdog also expressed concern.
"We are worried by assassinations by people wearing masks," Sao Paulo police ombudsman Antonio Funari Filho said.
Sao Paulo Governor Claudio Lembo denied that summary killings have taken place.
Sao Paulo police chief Marco Antonio Desgualdo said gangs may be taking advantage of the situation to settle scores with rivals.