Rescue crews airlifted a 14-year-old boy to Phoenix Children's Hospital after a crash on Daisy Mountain Trail Friday morning, according to the Maricopa County Sheriff's Office.

The boy suffered a leg injury and serious head trauma, MCSO said. His injuries are considered life-threatening.

It's not clear what caused the crash, which an MCSO spokesperson first reported around 9:30 a.m.

Authorities have not provided any update on the boy's condition as of 2:30 p.m.