Saudi Arabia's powerful crown prince has said "only death" can prevent him from ruling over the kingdom for several years to come.

"Only God knows how long one will live, if one would live 50 years or not, but if things go their normal ways, then that's to be expected," Mohammed bin Salman said during a wide-ranging interview that aired on CBS news show 60 Minutes on Sunday evening.

When asked by CBS' Norah O'Donnell if anything could stop him ruling, Bin Salman replied: "Only death."