World dignitaries were expected to begin arriving in Saudi Arabia on Monday to offer condolences for the death of Crown Prince Sultan bin Abdul Aziz, whose successor is yet to be named.
US Vice President Joe Biden, Pakistani President Asif Ali Zardari and Malaysian Prime Minister Najib Razak were among the world leaders heading to the Saudi capital to offer condolences.
The body of Prince Sultan, who died Saturday in a New York hospital, was repatriated to Riyadh late Monday for a subdued funeral on Tuesday, in line with strict Islamic traditions applied in the ultra-conservative kingdom.
Saudi state television Al-Ekhbariya aired live pictures from Riyadh air base where Sultan's body was taken from the plane in an ambulance.
Ailing King Abdullah, 87, on a wheelchair and wearing a surgical mask, was at the base to receive the crown prince's body, television footage showed.
It is the first time that the seat of the heir to the throne becomes vacant in the history of the oil-rich Gulf state.
Prince Nayef bin Abdul Aziz, a half-brother of King Abdullah and the kingdom's internal security czar who has held the interior portfolio for over three decades, is touted as Sultan's most likely successor as heir.
King Abdullah, who is also the prime minister, had in 2009 appointed Prince Nayef, 78, as second deputy premier, in a move interpreted as putting him in line for the throne.
Sultan was the second deputy prime minister until the then crown prince Abdullah acceded to the throne in 2005.
Sultan's death comes also after Abdullah created in 2006 the Allegiance Council, comprised of 35 princes charged with deciding together with the reigning king who will be crown prince.
"The rules of the Allegiance Council stipulate that the crown prince would be chosen by the council," said Fahd al-Harthi, head of the Riyadh-based ASBAR Centre for Studies, Research and Communications.
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"But the royal decree of this system has stated that the current king and crown prince are not forced to abide by this regulation," he told AFP.
People in the region's power house sounded at ease about the issue of succession, with some hailing Nayef, known for being a conservative, as the best choice.
"I believe that Prince Nayef will be the next crown prince and this is a matter the Saudi people agree with, because the interior minister has a great experience in politics and security and we feel very comfortable with him," in office, said Hamad al-Nasser, 45.
"It will not make s big difference whether the Allegiance Council system is activated now or not, because all are agreed on Prince Nayef," added the public sector employee.
Ahmed Tayeb, 25, also sounded upbeat, expecting Nayef to be chosen.
"He is a good man, and has a strong personality. This is what we need, mainly given the current situation in the surrounding environment," he said.
Relations between the Sunni-dominated kingdom and Shiite Iran, its arch rival across the Gulf, are tense following an alleged Iranian plot to assassinate the kingdom's envoy to Washington.
Saudi Arabia also keeps a close eye on developments in neighbouring Bahrain and Yemen, as well as other countries hit by the so-called "Arab Spring" uprisings demanding regime change.
Except for small protests by the Shiite minority in Eastern Province, Saudi Arabia was largely spared from the wave of popular protest movements, which has so far unseated three Arab leaders.
Prince Nayef, who mobilised his servicemen to prevent the winds of change from buffetting the kingdom, publically thanked Saudis for ignoring calls for demonstrations.
He also led a campaign against Islamist militants after the kingdom was hit by a string of deadly Al-Qaeda attacks between 2003 and 2006.