RIYADH, Saudi Arabia -- Saudi Arabia's 86-year-old King Abdullah handed over duties to his crown prince on Monday and left to the United States for treatment over a blood clot and slipped disc, the palace said.
Saudi authorities have been unusually open in going public with the king's condition, apparently in an effort to prevent any speculation and reassure allies of the key Mideast nation and oil power. Personal issues within the royal family are often kept under strict wraps.
Photos showed the king at the airport, kissing his second deputy prime minister Prince Nayef bin Abdulaziz on the cheeks goodbye as he departed. Abdullah was seated in a plush chair on the tarmac, an IV catheter clearly inserted in the back of his hand. Pictures in newspapers over recent days have shown the king being pushed in a wheelchair -- though still looking hardy.
Late Sunday, Health Minister Abdullah al-Rabeeah went on state TV saying Abdullah suffered a slipped disc and that a blood clot was pressing nerves in his back, causing him pain.
"But I assure everyone that the king is in stable condition and enjoys good health and God willing will return in good health to lead this great nation," al-Rabeeah said. He added that the king had outlined a "policy of transparency" about his condition.
Abdullah on Monday issued a royal decree mandating Crown Prince Sultan, his half brother and heir to the throne, to "administer the nation's affairs" in his absence. Abdullah has temporarily handed over authorities in the past when he has travelled abroad for conferences or personal trips, though this was the first time for health reasons.
The 85-year-old Sultan has his own health issues: He underwent surgery in New York in February 2009 and has spent much of the time since at a palace he has in Agadir, Morocco, recuperating. Sultan arrived Sunday in Saudi Arabia from Morocco to step in when the king left for treatment.
The palace announced Abdullah's departure on Monday "for medical tests." It did not specify where the king would be treated.
Abdullah rose to the throne of this key U.S. ally and oil power in 2005 after the death of King Fahd, another of his half brothers, though he had already been a de-facto ruler for half a decade.
The top of the line for the throne in Saudi Arabia is populated by royals of advanced age, raising questions about where the succession could go in the longer term. After Abdullah and Sultan, Nayef -- in his late 70s -- is widely seen as the best positioned to be next in line.
Since its creation in the 1930s, modern Saudi Arabia has been ruled by the sons of its founder, King Abdul-Aziz, who had dozens of children from several wives before his death in 1953.
In an attempt to formalize the succession system, Abdullah in 2006 set up the Allegiance Council, a body that is composed of Abdul-Aziz's sons and grandsons, who will vote by a secret ballot to choose future kings and crown princes. The council's mandate will not start until after the reigns of Abdullah and Sultan are over.