Saudi Arabia arrested 10 princes and dozens of former government ministers on Saturday, reports said, in a major purge immediately after an anti-corruption commission was established, reports Daily Mail Online.
Separately, the powerful heads of the Saudi National Guard, an elite internal security force, and the navy were replaced in a series of high-profile sackings that sent shock waves in the kingdom.
The developments follow a political crackdown in September as Crown Prince Mohammed bin Salman, set to be the first millennial to occupy the Saudi throne, cements his grip on power.
"Arrest of 10 princes and dozens of former ministers in Saudi Arabia," Saudi-owned Al Arabiya television reported, citing unnamed sources.
The news of the arrests came soon after the anti-corruption commission, headed by Prince Mohammed, was established by royal decree.
Saudi news websites said Saudi billionaire Prince Al-Waleed bin Talal was among those arrested, but there was no official confirmation. The prince was not immediately reachable for comment.
An aviation source told AFP that security forces had grounded private jets in the Red Sea city of Jeddah, potentially to prevent any high-profile figures from leaving.
"The breadth and scale of the arrests appears to be unprecedented in modern Saudi history," said Kristian Ulrichsen, a fellow at the Baker Institute for Public Policy at Rice University.
"The reported detention of Prince Al-Waleed bin Talal, if true, would send shockwaves through the domestic and international business community."
The arrests come less than two weeks after Prince Mohammed welcomed thousands of global business titans to Riyadh for an investment summit, showcasing his economic reform drive for a post-oil era.
The 32-year-old crown prince, often known as MBS, has projected himself as a liberal reformer in the ultra-conservative kingdom with a series of bold moves including the decision allowing women to drive from next June.
Already viewed as the de facto ruler controlling all the major levers of government, from defence to the economy, the prince is widely seen to be stamping out traces of internal dissent before a formal transfer of power from his 81-year-old father King Salman.
In September the authorities arrested about two dozen people, including influential clerics, in what activists denounced as a coordinated crackdown.
Analysts said many of those detained were resistant to Prince Mohammed's aggressive foreign policy that includes the boycott of Gulf neighbour Qatar as well as some of his bold policy reforms, including privatising state assets and cutting subsidies.