A teenage boy is dead and another boy is in hospital in a critical condition following a jet ski crash.
Emergency crews were called to Tom Uglys Bridge at Sylvania, in Sydney's south, just after 6pm AEST following reports of people floating in the water.
A 15-year-old boy was found to be deceased in the water and unable to be revived, police said.
A 14-year-old boy was treated at the scene for a severed arm and taken to Sydney Children's Hospital by paramedics.
He was in a critical condition on Tuesday night.
A crime scene has been established and investigations into the crash have begun.