With a crackdown on dissenters and a charm offensive to woo the kingdom's swelling youth population, Saudi Arabia's king-in-waiting Mohammed bin Salman is cementing his grip on power, analysts say.

The 32-year-old crown prince, often known as MBS, is set to be the first millennial to occupy the throne in a country where half the population is under 25, though the timing of his ascension remains unknown.

Already viewed as the de facto ruler controlling all the major levers of government, from defence to economy, MBS is seen as stamping out traces of internal dissent before any formal transfer of power from his 81-year-old father King Salman.

Authorities last week arrested around two dozen people, including influential clerics, in what activists decried as a coordinated crackdown.

Analysts say many of those detained are resistant to MBS's aggressive foreign policy that includes the boycott of Gulf neighbour Qatar as well as some of his bold reforms, including privatising state assets and cutting subsidies.

Saudi officials have instead suggested a foreign plot to overthrow the government, without disclosing details.

“In recent years we cannot recall a week in which so many prominent Saudi Arabian figures have been targeted in such a short space of time,” said Samah Hadid, a director at Amnesty International.

Meteoric rise

To analysts, MBS's meteoric rise has seemed almost Shakespearean in its aggression and calculation.

In June, he edged out a 58-year-old cousin, Prince Mohammed bin Nayef, to become heir to the throne. At the time, Saudi television channels showed the bearded MBS kissing the hand of the older prince and kneeling before him in a show of reverence.

Western media reports later said that the deposed prince had been placed under house arrest, a claim strongly denied by Saudi authorities. Foreign diplomats predict MBS could well be in control of Saudi Arabia for at least half a century.

“I can't say when the formal ascension of Mohammed bin Salman might happen, but the real transfer of power has already happened — he is effectively ruling Saudi Arabia,” Perry Cammack, a fellow at the Carnegie Endowment for International Peace, told AFP.

“With the (older) generation having now left the scene and his main younger rivals having been removed, Mohammed is primed to enjoy a dominance over Saudi Arabia unseen since the rule of Abdulaziz, who founded the modern Saudi kingdom in the 1930s,” he added.

With his youth a novelty in a country accustomed to ageing rulers, MBS has sought to woo young Saudis by putting sports and entertainment on the cutting edge of his reform effort, dubbed Vision 2030, at the risk of riling conservatives.

Public cinemas have long been banned inside the kingdom and there are few outlets for leisure activities.

MBS made a rare appearance this month in the football match that saw Saudi Arabia qualify for next year's World Cup. Alone in what appeared to be a bullet-proof royal box, the smiling prince flashed the victory sign — an image embossed on a new government poster for Vision 2030.

“The image perfectly captures two aspects of his power: his appeal to youth and to nationalism,” Kristin Diwan, from the Arab Gulf States Institute in Washington, told AFP.

“National pride is replacing the appeal of Islamism. And sports and other forms of entertainment are compensating youth for the weakness of the welfare state,” Diwan said.

A slump in oil prices has prompted Saudi Arabia to take steps to reduce the kingdom's generous welfare system after decades of using its vast energy resources to pay generous salaries and benefits.

Generational shift

This direct outreach to youth amid Saudi Arabia's transition to a post-oil era marks a clear departure from the past, when previous rulers appeared more inclined to court society's elders out of a deference to age.

But sluggish economic growth and soaring youth unemployment could hinder MBS's outreach.

His reform plan seeks to reduce reliance on oil and develop the kingdom's industrial and investment base to generate more private-sector jobs for young Saudis.

But recent reports that the government is rejigging its reform strategy, which has already fallen short in key areas, is a sign that “broader opposition to reform is building,” said research firm Capital Economics.

“His own youth, his tendency to centralise power, and his rapid changes to foreign policy have all alienated some of the senior ruling family members, while his changes to the economy have upset some of the merchant families,” Jane Kinninmont, from the London-based Chatham House, told AFP.

“Building up a youth support base may help MBS compensate for alienating some of the supporters that Saudi princes have traditionally counted on,” said Kinninmont.

MBS, who boasts of close ties to the White House, also appears to be empowering third-generation royals, with several younger princes holding deputy positions in various ministries and regional governments.

A series of full-page ads in Saudi newspapers recently extolled the virtues of the “charismatic” prince, tackling the unease in some quarters over his youth and perceived inexperience.

“His teachers describe him: He has never been part of a problem,” said the ad by a regional men's magazine that profiled MBS, splashed with pictures from his childhood. “Takes initiative and acts older than his age. “