Saudi Arabia's Crown Prince Nayef bin Abdul-Aziz al-Saud died Saturday, eight months after becoming heir to the throne. He was in his late 70s.
A statement carried by state media said Prince Nayef "died outside" Saudi Arabia. News reports said he died in the Swiss city of Geneva, where he recently traveled to seek treatment for an undisclosed illness.
The Royal Court said a "funeral prayer" will be held for him on Sunday in Makkah province.
U.S. President Barack Obama offered King Abdullah, the royal family and the Saudi people his "deepest condolences." A White House statement said that "under Prince Nayef's 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."
Prince Nayef, a former interior minister, was named crown prince last October following the death of Prince Sultan bin Abdul-aziz al-Saud. As crown prince, he would have assumed the throne upon the death of King Abdullah, who is in his late 80s.
His most likely successor will be Prince Salman, King Abdullah's brother, 76, who was made defense minister in November after serving more than four decades as governor of Riyadh.
Crown Prince Nayef was closely aligned with the kingdom's conservative clerics.
Middle East analyst Simon Henderson tells VOA, one of the crown prince's most notable achievements as interior minister was leading efforts to try to rid the kingdom of al-Qaida forces.
"It's his leadership which has been leading the Saudi efforts against al-Qaida in the kingdom although it's one of his sons, Mohammed bin Nayef, who has emerged as the leading counterterrorism figure in the kingdom," Henderson said.
Analysts say the next crown prince will probably be chosen by the Allegiance Council, a group that includes relatives of the crown prince.