Comanchero bikie boss Tarek Zahed is in a critical condition and his brother Omar has died after they were sprayed with bullets in the foyer of a gym in Sydney's west.
Emergency services were called to the Body Fit gym on Parramatta Road in Auburn after reports of a shooting at about 8pm on Tuesday.
Omar Zahed, 39, was treated for multiple gunshot wounds to his stomach, arms and legs.
"He was in cardiac arrest and sadly could not be saved," NSW Ambulance said in a statement.
Tarek Zahed, 41, suffered up to 10 gunshot wounds to his body, including to his head, and was taken to Westmead Hospital in a critical condition.
He has since undergone surgery and police say he remains in a stable condition.
Police found two Audis on fire in the nearby suburbs of Berala and Greenacre a short time after the attack.
Multiple crime scenes have been established and Homicide Squad detectives are leading the investigation under Strike Force Leary, with help from the Criminal Groups and Raptor Squads, as well as local police.
Police are targeting known members and associates of involved criminal networks.
The shooting comes just two weeks after gangland figure Mahmoud 'Brownie' Ahmad was gunned down on a Greenacre street.
NSW Police Commissioner Karen Webb said the latest shooting could have been retaliation for the killing of Ahmad.
"We can't rule it out.
"Some of these people are in conflict with a number of other groups and it is hard to pinpoint if it is direct retaliation or not," she told Sydney radio 2GB on Wednesday.
Thirty more officers have joined Strike Force Raptor, which deals with outlaw motorcycle gang criminal activity.
"Enough is enough," she said.
"The community in southwest Sydney, western Sydney, have had enough."
NSW Police had warned Tarek Zahed there was a bounty on his head.
"Some of these people think they're invincible," Commissioner Webb said.
"You try and warn them but they just live their lives like they are larger than life."
NSW Labor has renewed its calls for Premier Dominic Perrottet to take action on western Sydney gang violence.
The premier said the Raptor Squad was well equipped and warned criminals there was zero tolerance for gang activity.
"They're going to hunt you down and they're going to lock you up," Mr Perrottet said, adding police would be given any extra resources required and people should not feel unsafe in their neighbourhoods.
"We have one of the lowest crime rates in recorded history in our state," he said.
Last week, Investigations and Counter Terrorism Deputy Commissioner David Hudson told a parliamentary hearing there had been 11 gang-related homicides in the last two years sparked by rivalries in Sydney's criminal underworld.
Since June 2020, there have been more than 40 major known violent incidents between gangs in NSW.
Police are also investigating a targeted shooting at a home on Milford Road, Londonderry, in Sydney's northwest, just before 9pm on Tuesday.
Police say a 37-year-old man was shot in both legs by a man wearing hi-vis clothing and a face covering who burst into the home.
The injured man was treated by paramedics and taken to hospital in a serious but stable condition.