DUBAI - Saudi Arabia's Crown Prince Sultan bin Abdul-Aziz is in "excellent health" after being treated for an illness and will return home "after a few weeks", his son, Prince Khaled bin Sultan, was quoted as saying.

Prince Khaled's remarks were carried by the Saudi Press Agency (SPA) late on Sunday.

State media said in April that Prince Sultan had arrived in Morocco for rest and recreation after undergoing treatment in the United States, including unspecified surgery in February.

Prince Sultan went to the United States for medical tests in November, then to Morocco for a prescribed convalescence before flying back to New York.

Saudi media at the time described treatment received by Prince Sultan, believed to be about 84, as successful but did not specify the ailment for which he was being treated.

In March, King Abdullah appointed Interior Minister Prince Nayef bin Abdul-Aziz as second deputy prime minister, a promotion that would normally place him second in line to the throne after Sultan.

The position means he will run the kingdom, an absolute monarchy, when both the monarch and crown prince are away.

Al Qaeda launched an unsuccessful campaign of violence to destabilise the Gulf Arab country, the world's biggest oil exporter, from 2003 to 2006.

Analysts do not expect any change in oil policy with a change of monarch or crown prince.

Prince Sultan had an intestinal cyst removed in Saudi Arabia in 2005 and he visited the Swiss city of Geneva in April 2008 for what were described as routine tests.