It was billed as a crackdown on corruption. But the astonishing arrests of nearly a dozen members of Saudi Arabia's royal family were intended to send a clear message that the young heir to the throne is serious about modernizing the Kingdom of Saudi Arabia.

The detentions were also meant to show that senior princes are no longer untouchable.

The moves that continued on Monday sidelined at least 11 princes and scores of current and former ministers and business officials. While the exact charges against them remain unknown, they came just hours after Crown Prince Mohammed bin Salman established a committee to combat corruption.

A royal decree on Saturday said the roundup was in response to "exploitation by some of the weak souls who have put their own interests above the public interest, in order to, illicitly, accrue money."

Saudi Prince Alwaleed bin Talal owns shares in several Western companies, including Twitter and Citigroup. (Fahad Shadeed/Reuters)

The arrests ensnared one of the world's richest men, Prince Alwaleed bin Talal, who owns significant shares in a wide variety of Western companies, from the ride-sharing service Lyft, to holdings in the Canadian-based Four Seasons and Fairmont hotel chains.

The crackdown now gives the 32-year-old crown prince and his father King Salman, 81, control over the kingdom's security forces and military, after the princes who were in charge of the navy and National Guard were detained.

And the shakeup solidifies Prince Mohammed's role as the most important man in the kingdom, clearing the way for him to press ahead with social and economic reforms, while elevating the cold war between Saudi Arabia and regional rival Iran.

Returning to 'moderate Islam'

The crown prince has remained silent about the late-night arrests on Saturday, but his comments nearly three weeks ago that he wants to "eradicate" extremism in Saudi Arabia were almost as stunning.

"We are only returning to what we used to be, to moderate Islam, open to the world and all religions," Prince Mohammed said at an investors conference in the capital, Riyadh. "We won't waste 30 years of our lives dealing with any extremist ideas. We will eradicate extremism."

Saudi Arabia is a nation founded in the tradition of Wahhabism, an ultraconservative brand of Islam that has been criticized abroad for feeding both intolerance and terrorism.

The religious establishment has long policed public behaviour by ensuring morality and adherence to Islamic law. But the government began to take steps last year to curb the authority of the religious police, limiting their ability to arrest members of the public.

Women in Saudi Arabia will be permitted to drive next summer, under a package of reforms backed by the crown prince. (Hasan Jamali/Associated Press)

Under reforms linked to Prince Mohammed, Saudi women will be allowed to drive beginning next summer.

The government is also trying to bring more forms of public entertainment. Earlier this year, some Saudis — including women — dressed up as superheroes at the kingdom's first Comic-Con event.

These reforms, aimed at refocusing the kingdom's economy away from oil and modernizing society, have appealed to many young Saudis — who no longer want to have to travel to London or Dubai to see a pop concert — and are hungry for more freedoms.

Eye on aspirations of young Saudis

"The crown prince's eyes are on ordinary, young Saudis who are becoming more restive and are asking questions about the gap between their aspirations and the reality on the ground," said Fawaz Gerges, professor of international relations at the London School of Economics.

"The clampdown against corruption resonates with ordinary Saudis who feel that the state has been asking them to accept belt tightening while, at the same time, they see corruption and the power elite accumulating more wealth," Gerges told CBC News.

Saudi authorities also want to build a new travel destination along the Red Sea coast, where women would be free to wear whatever they wanted when heading to the beach — something unheard of in a nation where modesty is a central vanguard.

But the prospect of a more open and modern Saudi Arabia has angered the conservative religious clerics, who have wielded considerable power in recent decades.

A display from Comic-Con in Jeddah, Saudi Arabia, in February 2017. (Courtesy saudicomiccon.com)

It seems that Prince Mohammed is prepared to stand up to them, as he pushes for a more moderate approach to Islam — hoping to improve the kingdom's image abroad.

Accelerating war with Yemen

But the crown prince continues to face critics in some foreign circles for his agenda outside the country's border.

Prince Mohammed has accelerated the Saudi war in neighbouring Yemen, where a bloody conflict with Iranian-backed Houthi rebels has raged since 2015.

The United Nations in September reported that more than 5,000 civilians have been killed in the conflict. The UN's human rights chief blamed the majority of the deaths on the Saudi-led coalition.

A boy injured in a Saudi-led airstrike lies in a hospital bed in Saada, Yemen. (Naif Rahma/Reuters)

There are fears of escalation after Houthi rebels fired a ballistic missile at Riyadh on Saturday. The missile was destroyed near the city's airport.

Just hours earlier, the resignation of the prime minister of Lebanon rocked the already volatile Middle East.

Prime Minister Saad Hariri, who announced his departure from Riyadh, said he was stepping down because he was worried about an assassination plot — blaming Iran and the Lebanese militant group Hezbollah, which Tehran supports, for his decision.

Saudi Arabia's King Salman bin Abdulaziz Al Saud meets with former Lebanese Prime Minister Saad Hariri in Riyadh, Saudi Arabia. (Saudi Press Agency)

Israel's prime minister Benjamin Netanyahu tweeted that the resignation was a "wake-up call for everyone."

The Middle East is "experiencing the attempt of Iran to conquer the Middle East, to dominate it and subjugate it," Netanyahu told the BBC.

The events of the weekend sent seismic waves across the Middle East and raise concerns of a new period of even greater uncertainty in the region.

Rivalry with Iran intensifies

With the war against ISIS winding down in Syria and Iraq, there are concerns that the battle for dominance of the Middle East between Iran and the Saudis could also escalate.

With Syria's Bashar al-Assad still firmly in power in the presidential palace in Damascus, largely thanks to the backing of Russia and Iran, the Saudis have failed at their attempt to force him out.

"Iranian influence is rampant in Lebanon, Syria and Iraq," wrote Bruce Reidl, the director of the Intelligence Project at the Brookings Institute in media site al-Monitor.

"The kingdom is at a crossroads: Its economy has flatlined with low oil prices; the war in Yemen is a quagmire… It is the most volatile period in Saudi history in over a half-century."