Prominent billionaire Al-Waleed bin Talal was among the princes arrested late Saturday, a government source told AFP, immediately after a new anti-corruption commission headed by Crown Prince Mohammed bin Salman was established by royal decree.
Separately, the head of the Saudi National Guard, once a leading contender to the throne, as well as the navy chief and the economy minister were replaced in a series of high-profile sackings that sent shock waves through the kingdom.
The dramatic shake-up comes at a time of unprecedented social and economic transformation in ultra-conservative Saudi Arabia, as Prince Mohammed steps up his reform drive for a post-oil era.
Saudi-owned Al Arabiya television reported that 11 princes, four current ministers and dozens of ex-ministers were arrested as the commission launched a probe into old cases such as floods that devastated the Red Sea city of Jeddah in 2009.
The government official gave AFP a list of 14 of the most high-profile names including Prince Al-Waleed, ranked among the richest men in the world.
The information ministry separately said the bank accounts of those arrested will be "frozen" and any assets related to the corruption cases will be registered as state property.
"The suspects are being granted the same rights and treatment as any other Saudi citizen," attorney general Sheikh Saud al-Mojeb said in a statement, adding that a number of investigations had been initiated.
"A suspect's position or status does not influence the firm and fair application of justice."
'A new era'
Shares in Kingdom Holding, 95 percent of which is owned by Prince Al-Waleed, dived 9.9 percent as the Saudi stock exchange opened Sunday after reports of his arrest. The share price later recovered some of its losses to end the day down 7.6 percent.
In a statement Kingdom Holding said it was "aware" of Saturday's developments but insisted that it was "business as usual" after the chief executive of the company was assured of support from the government.
Saudi Finance Minister Mohammed al-Jadaan said the crackdown "heralds a new era and policy of transparency, clarity and accountability".
"The decisive decisions will preserve the investment environment and boost trust in the rule of law," the Saudi Press Agency quoted him as saying.
The kingdom's top council of clerics also lauded the anti-corruption efforts as "important", essentially giving religious backing to the crackdown.
An aviation source told AFP that security forces had grounded private jets at airports, possibly to prevent high-profile figures from leaving the country.
There was fevered speculation on social media that the arrested figures were being held at Riyadh's Ritz Carlton, a palatial hotel originally planned as a palace for guests of the royal family.
The hotel appeared to be closed off to the public on Sunday and its website said the property was fully booked.
"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 shock waves through the domestic and international business community," Ulrichsen told AFP.
The purge comes less than two weeks after Prince Mohammed welcomed thousands of global business leaders to Riyadh for an investment summit, showcasing his reform drive that has shaken up the kingdom.
Meteoric rise
It follows a wave of arrests of influential clerics and activists in September as the 32-year-old prince, often known as MBS, consolidates his hold on power.
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.
The latest purge saw Prince Miteb bin Abdullah sacked as the head of the National Guard, an elite internal security force. His removal consolidates the crown prince's control of the kingdom's security institutions.
To analysts, Prince Mohammed'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.
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.
At the same time, he 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.
