Kuwait’s 91-year-old ruler underwent a “successful” surgery Sunday that required the oil-rich nation’s crown prince to be temporarily empowered to serve in his place, its state-run news agency reported. Kuwait has yet to elaborate what required Sheikh Sabah Al Ahmad Al Sabah to seek a previously unannounced medical treatment beginning Saturday. However, Sheikh Sabah’s sudden surgery could inspire a renewed power struggle within Kuwait’s ruling family. The state-run KUNA news agency had described Sheikh Sabah’s hospitalization Saturday as “medical checks,” citing a statement from the country’s royal court. Several hours later, KUNA published a second report saying that 83-year-old Crown Prince Nawaf Al Ahmad Al Sabah had assumed some of Sheikh Sabah´s powers temporarily, without explaining why that was necessary. However, a copy of the ministerial decree posted by Kuwait’s official gazette, Kuwait Al-Youm, and seen by The Associated Press on Sunday said the crown prince would be empowered for “the duration of a surgical procedure until the health event is over.” The decree did not elaborate. Kuwait’s Information Ministry did not immediately respond to a request for comment, though minutes later the state-run KUNA news agency reported Sheikh Sabah underwent a “successful” surgery, without elaborating. “May God bless his Highness and grant him a speedy recovery,” the KUNA report said, citing a royal court statement. Sheikh Sabah, a widely beloved ruler in this OPEC-member nation, took power in 2006 just nine days into the rule of the ailing Sheikh Saad Al Abdullah Al Sabah. Concerns mounted during Sheikh Saad’s brief reign as he was seen in public only in a wheelchair and did not speak. However, Sheikh Sabah’s ascension upset an informal power-sharing arrangement between branches of Kuwait’s ruling family. While Kuwait has since remained politically stable with the most-empowered parliament of any Gulf Arab nation, there have been internal power struggles behind the scenes of his rule. Kuwait, a nation home to 4.1 million people that’s slightly smaller than the US state of New Jersey, has the world´s sixth-largest known oil reserves. It has been a staunch US ally since the 1991 Gulf War expelled the occupying Iraqi forces of Saddam Hussein. Today, Kuwait hosts some 13,500 American troops, many at Camp Arifjan south of Kuwait City, which is also home to the forward command of US Army Central.