Saudi crown prince to return from US next week: Saudi official

"He's expected to arrive either Thursday or Friday, God willing," the unnamed official told Reuters.

The 78-year-old prince went to Cleveland, Ohio a month ago for “scheduled medical tests.”

Last October, Nayef was appointed as the new crown prince of the kingdom after ex-Crown Prince Sultan died of colon cancer in New York.

Prince Nayef, who has been interior minister for nearly four decades, would take over the rule of the kingdom in the event of the death of King Abdullah.

The poor health among the aging royal family in the Persian Gulf state deepens the power vacuum amid a wave of protests over the persisting brutal crackdown on the Saudi people.

Saudi Arabia's east has been the scene of anti-government protests since February 2011.