Teenager shot in head remains critical

A 19-year-old is fighting for life in a Sydney hospital after he was shot in the head, reportedly during a game of Russian roulette.

The teenager underwent surgery in Westmead Hospital on Sunday afternoon but remains in a critical condition.

Police have confirmed the young man sustained a gunshot wound to the head in Pitt Town, in Sydney's northwest, and investigations into the circumstances continue.

The Nine Network reported on Saturday that three friends who were in the car with the teenager told investigators he was playing Russian roulette.

No one has been charged.