US President Barack Obama said Crown Prince Nayef, who had been next in line to rule Saudi Arabia, the world's top oil exporter, had for decades "dedicated himself to the security of Saudi Arabia as well as security throughout the region."
Under his leadership, the United States and Saudi Arabia developed a strong and effective partnership in the fight against terrorism, one that has saved countless American and Saudi lives. On behalf of the American people, I would like to offer my deepest condolences to King Abdullah, the royal family, and the people of Saudi Arabia.
Seen as a key ally for the West, Saudi Arabia has provided critical intelligence to foil al Qaeda plots, bankrolled pro-Western Arab governments and has supported Washington's attempts to isolate Iran.
More top news
Queens Parks Rangers defender Rio Ferdinand has announced his retirement from football after his wife's recent death.
A promising start to the weekend - fine and bright for most of us but showers will crop up across northern Scotland.
A war veteran who was burgled said he is overwhelmed after thousands of pounds were raised for him by people he had never met.