King Salman's elder half-brother, who was the tenth son of the country's founding monarch, has died at age 96.
Prince Bandar bin Abdulaziz Al Saud was the eldest living son of King Abdulaziz Al Saud.
Prince Faisal bin Turki announced the death on Twitter on Sunday.
Prince Bandar's sons hold important posts: Prince Faisal bin Bandar is governor of Riyadh; Prince Abdullah bin Bandar heads the National Guard; and Prince Khalid bin Bandar serves as an adviser to King Salman.
UAE President Sheikh Khalifa sent a cable of condolences to the Custodian of the Two Holy Mosques, King Salman, on the death of Prince Bandar.
Sheikh Mohammed bin Rashid, Vice President of the UAE and Ruler of Dubai, and Sheikh Mohamed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the UAE Armed Forces, also sent messages of condolences.
Sheikh Dr Sultan bin Muhammad Al Qasimi, Ruler of Sharjah, Sheikh Ahmed bin Sultan Al Qasimi, Deputy Ruler of Sharjah, Sheikh Sultan bin Mohammed Al Qasimi, Crown Prince and Deputy Ruler of Sharjah and Sheikh Abdullah bin Salem Al Qasimi, Deputy Ruler of Sharjah, sent similar messages of condolences to King Salman.