The son of murdered Saudi journalist Jamal Khashoggi on Monday welcomed the court verdict that saw five people sentenced to death over the killing, saying justice had been served.

"Fairness of the judiciary is based on two principles, justice and swift litigation," wrote the son, Salah Khashoggi, on Twitter.

"Today, justice was served to children of ... Jamal Khashoggi. We affirm our confidence in the Saudi judiciary at all levels," he added.