Riyadh–Saudi King Abdullah is to be treated in the United States for a back problem, with ailing Crown Prince Sultan bin Abdul Aziz returning from Morocco to take over, officials said.
The king will leave on Monday to "complete his medical examinations and follow-up treatment based on the recommendation of the medical team," the royal court said in a statement carried by the official news agency SPA.
Health Minister Abdullah al-Rabeeah told state television that the monarch was "in a stable state and is well."
He will "undergo further medical examination and continued treatment … at a centre specializing in spinal problems" in the United States, the minister said.
Crown Prince Sultan is to return to the oil-rich kingdom from Morocco after "his highness has enjoyed a private holiday," another official statement said.
Sultan, who has spent nearly 12 weeks at his palace in Agadir, will take up the reins during Abdullah's absence, a Saudi official told AFP, on condition of anonymity.
Abdullah, 86, is to be treated for a herniated disc and "blood accumulation" around the spine, the official said.
He added that Prince Sultan, who has himself been receiving treatment for the past two years for what analysts and diplomats believe to be cancer, was due back on Sunday.
Any transfer of power in the absolute monarchy, founded in 1932, is keenly watched by oil markets as the vast nation sits on one quarter of the world's known oil reserves.
Crown Prince Sultan, as defense minister for the past five decades, played a key role in building up the Gulf state's military in a volatile region and boosting the power of the ruling family.
His long tenure as defense and aviation minister has been marked by multi-billion-dollar procurement scandals, including the Yamamah deals with Britain, but his influence never waned until his health started to deteriorate.
Sultan's long absence abroad as he fought his illness had held up government decisions and facets of Abdullah's ambitious reform program, as well as raising questions about the future shape of the monarchy.
The crown prince, who is 79 according to an official biography and approaching 85 years according to a specialist close to the royal family, has not been very active since going abroad for medical treatment.
The deteriorating health of both king and crown prince serve notice of possible political changes looming for Saudi Arabia, a key player in the Middle East.
Abdullah, king since 2005, had reduced his duties since June this year over health problems which were never previously officially disclosed.
On 12 November, the royal court said he was suffering from a herniated disc, a painful but treatable spinal ailment.
"Doctors have advised him to rest as part of his therapy," said a brief statement carried at the time by SPA, which added that the announcement was in line with the monarch's "principle of transparency."
That statement marked a shift toward more openness in Saudi Arabia, where health problems of the sovereigns and princes are usually state secrets.
On Friday, the king underwent tests at King Faisal hospital in Riyadh after a new flare-up of pain. Official reports said he had an "accumulation of blood" around the spinal cord.
In a television appearance last week in which he was seen to use a cane, King Abdullah said he was in good health but had something "bothering" him.
On Saturday, an expected — but never officially announced — visit by Egyptian President Hosni Mubarak became a phone call between the two leaders instead.
The Saudi royals who have dominated the government for 30 years or more are all aged and have been treated for various health problems, usually never defined, during the past year.
Prince Nayef, 76, Sultan's full brother and considered second in line to the throne, has also had unspecified treatment in the past 12 months. He has been interior minister for 35 years.
