A teenager was allegedly asked if he was a member of a notorious street gang before he was ambushed by a group of masked attackers armed with knives and stabbed to death. Police are exploring whether the violent incident is part of a flare-up in Sydney’s “postcode wars”.

Zac McRae and Vimlesh Chand, both 19, were set upon by four masked assailants at the Mount Druitt bus and train interchange around 10pm on Thursday. Shortly after, three ambulance crews arrived to find McRae and Chand with multiple stab wounds.

The scene at Mount Druitt on Wednesday night.

The scene at Mount Druitt on Wednesday night.Credit: Nine News

McRae died after being stabbed in the chest, while Chand was taken to Westmead Hospital in a serious but stable condition after receiving treatment from paramedics for stab wounds to his chest and arm. A third person with them was assaulted, but not seriously injured.

Mount Druitt police area commander Darrin Batchelor said Chand was stabbed through the “entirety of his arm” before the knife penetrated his chest. Doctors reported he was “extremely lucky” to survive the “violent, frenzied attack”, Batchelor said.

One of the attackers is alleged to have asked McRae, “Are you 67?” referring to the so-called 67 gang linked to the suburb of Doonside, which has the postcode 2767. The attackers fled the scene and are yet to be arrested.

While police are yet to establish which, if any, gangs the victims or attackers are linked to, they are investigating tensions between 67 and RFA (Ready For Anything), a rival gang from Mount Druitt.

Police conduct a line search on the train tracks near Mount Druitt station.

Police conduct a line search on the train tracks near Mount Druitt station. Credit: Nine News

A police source with knowledge of the investigation told the Herald that detectives were investigating the victims’ possible links to local street gangs and whether any associations were the motivation for the attack.

Police believe the victims were ambushed by a group of attackers, who were wearing face coverings and dark clothing. Investigators have been told that one of the masked assailants asked the victims what gang they were affiliated with before the attack.