New Saudi King Salman, 79, made key nominations Friday paving the way for a "second generation" to succeed him, while cementing power for his branch of the royal family.
The appointments of his son, Prince Mohammed bin Salman, as defence chief, head of the royal court and special adviser, and of Interior Minister Prince Mohammed bin Nayef as second in line to the throne, coincided with King Salman's first public remarks as king.
They came hours after the death of King Abdullah, aged about 90, and the naming of the deputy crown prince, Moqren, as the new heir to the throne.
Moqren would be the last of the sons of the kingdom's founder, Abdul Aziz bin Saudi, to sit on the throne.
His nephew, 55-year-old Prince Mohammed bin Nayef, would be the first of the "second generation," or grandsons of Abdul Aziz.
Under Saudi law, the monarch must be a son or grandson of Abdul Aziz, who founded the country in 1932 and died in 1953.
Since then the throne has systematically passed from one of his sons to another, but many are now dead or aged.
In March 2014, King Abdullah named Moqren, the youngest of Abdul Aziz's 45 sons, to the new position of deputy crown prince with the aim of smoothing succession hurdles.
As interior minister, Prince Mohammed bin Nayef served in a post also held by his father, the late Nayef bin Abdulaziz.
He was in charge of a crackdown on Al-Qaeda following a wave of deadly attacks in the Gulf state between 2003 and 2007.
- Security a 'priority' -
London-based analyst Abdelwahab Badrakhan said the "smooth change" in naming Prince Mohammed bin Nayef demonstrates that the family has "decided to transfer power to the second generation."
Signup to our newsletter and follow us on Facebook and Twitter!
Prince Mohammed bin Nayef's background implies that as king he would "prioritise security," a fact that "comforts foreign partners, especially the United States," he said.
His appointment helps to solidify control by the new king's Sudayri branch of the royal family, named after Hissa bint Ahmad al-Sudayri, the mother of Salman and his late brother, Nayef.
Their influence had waned under King Abdullah.
But Stephane Lacroix, professor at the Paris Institute of Political Science (Sciences Po), does not rule out possible rivalry in the future. He pointed out that King Salman's sons could benefit from their father's new position at the helm to "return to the competition."
The monarch pledged no change in the kingdom's direction.
"I pray to God to give me support," he said, wearing a dark, gold-fringed robe as he read from a binder in a wood-panelled room.
"We will remain, with God's strength, attached to the straight path that this state has walked since its establishment by King Abdul Aziz bin Saud, and by his sons after him," Salman said in a televised speech.
He also called for Muslim unity.
"The thing the Islamic ummah (nation) most needs is its unity and solidarity, and we will continue in this country to undertake all that can achieve unity... and the defence of the causes of our nation," the king said.
Regional heavyweight Saudi Arabia is the birthplace of Islam and home to the holy cities of Mecca and Medina.
Salman's comments come as war ravages parts of the Arab world including Libya, Syria, and two of the kingdom's neighbours, Iraq and Yemen.
Saudi Arabia, along with other countries in the Gulf, has joined a US-led air campaign against the Islamic State extremist group that has seized parts of Syria and neighbouring Iraq.