A significant shake-up in Saudi Arabia's line of succession and its senior leadership signals the emergence of a younger generation that analysts say is likely to champion an assertive foreign policy for the kingdom and seek to curtail the influence of rival Iran.
The reshuffling of key posts in the kingdom, announced Wednesday in a series of royal decrees, also marked a sidelining of some close allies of the late King Abdullah, who died in January and was succeeded by his half brother, Salman.
King Salman, 79, named a new crown prince and deputy crown prince, putting what could be a decades-long stamp on the conservative and secretive Saudi dynasty.
Prince Mohammad ibn Nayif, the deputy crown prince, was elevated to crown prince and heir apparent, the first time that a grandson of the kingdom's founding monarch has been designated as first in line to the throne.
The new crown prince has close ties to the United States, stemming primarily from his role at the forefront of the kingdom's counter-terrorism efforts, including Saudi Arabia's cooperation in the U.S.-led campaign to confront the militants of Islamic State. In 2009, he narrowly survived an attack by an Al Qaeda bomber who concealed explosives in a body cavity.
The king's son, Prince Mohammad ibn Salman, was named deputy crown prince, setting a likely seal on the eventual continuation of his father's royal lineage. Thought to be in his 30s, the prince was a relative unknown until January, when he became defense minister despite having no military experience. He has taken a leading public role in the military campaign in Yemen, which has been seen as a sign that the Saudis will take a more robust approach to foreign policy.
The Saudi royal family tree has dozens of branches, and succession issues involve complex alliances and rivalries. Salman nudged out as crown prince his half brother Prince Muqrin, who was close to the late king.
Analysts said the appointments concentrated power that for decades has been widely distributed within the huge royal family. And that, they said, could intensify jockeying for influence that could ultimately threaten the kingdom's stability.
"The anxiety that Washington should have is that there are clearly moves going on in Riyadh which could amount to a power struggle," said Simon Henderson, a Persian Gulf specialist at the Washington Institute for Near East Policy.
The shake-up in the world's top oil-exporting country comes at a time of extraordinary regional tumult. More than four years after "Arab Spring" uprisings, wars are being fought in Iraq and Syria, Libya has dissolved into a patchwork of armed fiefdoms, and Yemen has been ravaged by a Shiite Muslim insurgency and a Saudi-led military offensive against the rebels.
The air war in Yemen, now in its second month, has drawn harsh denunciations from Shiite rival Iran. Humanitarian groups have expressed alarm over the growing civilian casualty toll and widespread destruction in what was already the Arab world's poorest country.
The offensive against Yemen's Houthi rebels appears to still have Saudi domestic support despite such external criticism.
As part of the shake-up, Saudi Arabia's ambassador to Washington, Adel Jubeir, was named foreign minister, the first nonroyal to hold the post. The envoy, who has played a high-profile role in publicly explaining Saudi aims in Yemen, replaces Prince Saud al Faisal, who had served for decades.
With Saudi Arabia and Iran sparring over the Yemen intervention, Tehran was icily dismissive of the Saudi reshuffle. Ali Shamkhani, head of Iran's national security council, called it an "internal power struggle" and said, "Saudi Arabia has lost its status in the Islamic world."
Iranian state television on Wednesday aired an interview with the pilot of an Iranian plane that tried to land Tuesday at the international airport outside Sana, the Yemeni capital. The attempt prompted an airstrike by the Saudi-led coalition that seriously damaged the airport.
The pilot said the plane was carrying relief supplies.
Saudi Arabia accuses Iran of arming the Houthis, which Tehran denies.
King reported from Cairo and Richter from Washington. Special correspondent Ramin Mostaghim in Tehran contributed to this report.