Crown Prince Sultan, who was around 86, had been in the United States for medical treatment since June. His death has thrown his brother Prince Nayef into line to succeed King Abdullah as leader of the key oil producer country.
Saudi Arabia's King Salman bin Abdulaziz al-Saud on Wednesday dismissed the heir to the throne, Crown Prince Moqren bin Abdul Aziz bin Saud, and replaced him with the Interior Minister Mohammed bin Nayef.
Thousands gathered in Riyadh, Saudi Arabia, to pay their respects to King Abdullah, who died early on Friday.