RIYADH (AP) ― Saudi Arabia kept power within the surviving, aging sons of the kingdom’s founding patriarch Monday by naming Defense Minister Prince Salman bin Abdul-Aziz as the new heir to the throne in a country both battling and embracing the upheavals across the Middle East.

The choice was expected, but the speed of the royal decree was not ― just a day after the burial of the late crown prince, Prince Nayef, who died last week in Geneva and was in the No. 2 position only since November.

Prince Salman, 76, is now the third successor for the 88-year-old King Abdullah in the past year.

It reflects the issues of health and age that will one day turn control of OPEC’s top oil exporter over to a younger generation. Yet it also displays the preference for cautious steps by ruling House of Saud, which must balance its role as one of the West’s main Middle East allies with its need to appease the ultraconservative religious establishment that gives the monarchy its legitimacy in the land of Islam’s holiest sites.

In Washington, President Barack Obama issued a statement praising Salman as “a man of deep faith who is committed to improving the lives of the people of Saudi Arabia and to the security of the region.’’ Obama wrote, “The United States looks forward to continuing our strong relationship with Crown Prince Salman in his new capacity as we deepen the longstanding partnership between the United States and Saudi Arabia.’’

Salman may be viewed a slightly less hard-line and dogmatic than Nayef ― the former interior minister ― but there are no suggestions that he harbors ambitions to challenge the clerics and push for reforms on women’s rights and the kingdom’s strict social codes.

“This is essentially a holding pattern for the country,’’ said Simon Henderson, a Saudi affairs expert at the Washington Institute for Near East Policy. “There are no real fundamental differences between Nayef and Salman.’’

But there is a host of new complexities facing the Saudi leadership in the coming years.

At home, Saudi authorities have set the tone for Gulf rulers trying to hold back dissent inspired by the Arab Spring. It has called out security forces to crack down on protests by its own Shiite minority, rounded up online activists and sent in troops ― under Salman’s command ― to neighboring Bahrain to help the embattled Sunni dynasty there against an ongoing Shiite-led uprising.

Gulf neighbors also have opened their treasuries to copy Saudi Arabia’s attempts to literally buy time in a population nagged by rising employment and nearly half under the age of 25. Saudi officials have promised more than $100 billion in state jobs and other handouts.

Meanwhile, Saudi officials have seized opportunities opened by the Arab Spring. King Abdullah has reinforced ties with monarchies in Morocco and Jordan, while becoming an open supporter of Syrian rebels in hopes of toppling Bashar Assad’s regime and dealing a serious blow to Iran, Assad’s ally and Saudi Arabia’s archrival.

Salman ― who wears a mustache and goatee like Abdullah ― has been as the center of all Saudi’s critical moves since the Arab Spring revolts began last year.

“This was a cautious moved planned well in advance,’’ said Sami al-Faraj, director of the Kuwait Center for Strategic Studies. “It sends the message that the House of Saud is not ready for a major generational change just yet.’’

In a possible nod toward the inevitable, the decree promoted Prince Ahmed from deputy interior minister to take Nayef’s place leading the ministry, which has played the front-line role in crackdowns on Islamic militants following the Sept. 11 attacks.

The move also appears to put Ahmed, believed to be in his early 70s, in a position to be in line for the throne.

Ahmed is believed to be the 31st son Saudi’s founding monarchy, King Abdul-Aziz, and could offer a position as a bridge between his era as the so-called “third generation’’ ― the hundreds of princes from Abdul-Aziz’ children.

Crispin Hawes, director of the Middle East and North Africa region for the policy think-tank Eurasia Group, said Saudi royal court seeks to “send a strong message of stability ... both of its supporters and enemies’’ in a time of fast-moving events in Syria and elsewhere ― including the next round of nuclear talks that opened Monday in Moscow between Iran and world powers.

Salman presents a figure more diverse than many in the Saudi inner circle.

He served for more than four decades in the influential post of governor of Riyadh, the capital, making him the host for VIPs and international envoys as the city grew from a desert outpost to a Gulf-style forest of skyscrapers. He is also the head of a family business network that include a stake in the pan-Arab daily newspaper Al-Sharq al-Awsat, an important media tool for Saudi’s rulers.

One of his sons, Prince Sultan, was the first Arab astronaut as part of a 1985 space shuttle mission.

The late Nayef was considered wary of even the modest changes brought by King Abdullah, including pledges to allow women to vote and run in the next municipal elections in 2015. Salman also is regarded a traditionalist, but not as deeply tied to the religious establishment and capable of flexibility.

He showed leniency when dozens of women drove through Riyadh in 1990 to challenge the kingdom’s ban on women driving.

In 2005, he reportedly intervened to release an Arab song contest winner, Hisham Abdel Rahman, after he was detained by the country’s feared morality police for being swarmed by male and female fans at a Riyadh mall.

Salman also is described as having an unofficial role as the royal family mediator for internal disputes.

Salman’s links to Saudi religious charities brought him into minor controversy as one of the defendants in a lawsuit by insurance companies that accused Saudi Arabia of funneling money to al-Qaida. A U.S. appeals court in New York had ruled in 2008 that the Saudi royal family and other defendants enjoy immunity from such lawsuits.

Salman has suffered at least one stroke that has left him with limited movement on his left arm, but the full extent of the health condition is unknown. He is known to keep a full work schedule and travels frequently, including a visit to Britain in April to meet with defense officials.

The Saudi ruling family rarely gives details on the medical status of top figures even when they are hospitalized. Salman took over the Defense Ministry after the death of his brother Prince Sultan in October ― which brought Nayef to the position of crown prince.

Salman and Ahmed are now the only politically active survivors from a powerful group known as the “Sudairi seven,’’ sons of the late King Abdul-Aziz and a favored wife, Hussa bint Ahmad Sudairi, whose marriage helped cement the king’s rule over the patchwork of tribes in Saudi Arabia.