From the stately rows of palm trees on its 52-acre grounds to the grand double staircase to the glittering ballroom chandeliers, it is easy to see why the 6-year-old Ritz-Carlton in Riyadh, the capital of Saudi Arabia, has played host to billionaires, heads of state and members of the Saudi royal family.

Which is why it is all the more jarring that former government ministers, prominent businessmen and members of the royal family — the House of Saud — are being held captive in the five-star hotel, which was swiftly converted over the weekend into what is almost certainly the world’s most luxurious prison.

In a shaky video that appears from its metadata to have been shot early this morning in the hotel’s Ballroom B, people can be seen lying on mats covered with brightly colored blankets in floral motifs while guards in dark uniforms are visible in the background. In a corner stands a rifle, which appears to be a U.S. standard military-issue M4, its civilian variant or a copycat.

Saudi Arabia finds itself in the midst of a crackdown on corruption that began Saturday night with the arrest of dozens of people, at least 11 of whom were princes, including the billionaire investor Prince Alwaleed bin Talal. By today, U.S. officials tracking the situation said that as many as 500 people had been rounded up in the ongoing sweep.

The country’s attorney general, Sheikh Saud al-Mujeb, said today that detainees had been subjected to detailed interrogations. He said the investigations were being conducted in secret to protect the integrity of the legal procedures and to ensure that the detainees’ high social status would not exempt them from justice.

Members of the royal family have been prohibited from leaving the country, sparking fear and concern. It was a striking turnabout for elites accustomed to lives of extreme privilege and the freedom to jet off to Paris, London or New York at the drop of a hat.

While the stated goal of the arrests was fighting corruption, some observers see the crackdown as part of the consolidation of power by the country’s young crown prince, Mohammed bin Salman.

Less than two weeks earlier, powerhouses of global capital — including Treasury Secretary Steven Mnuchin and Blackstone Group co-founder Stephen A. Schwarzman — were among the 3,500 invitees, estimated to control $22 trillion in assets, who streamed down the red carpet and into the hotel for the Future Investment Initiative, a conference that was nicknamed “Davos in the Desert.”

In May, the Riyadh Ritz was festooned with U.S. flags as the palatial hotel played host to President Donald Trump on his first trip abroad as commander in chief. His predecessor, President Barack Obama, stayed at the hotel in 2014.

Ballroom B, where the video footage appears to have been taken, is just shy of 20,000 square feet and can be used as a banquet room seating 1,400 people or a reception accommodating 2,000 people.

As with most public spaces in the kingdom, the hotel does not permit shorts, skirts or tank tops. It asks that guests dress modestly, either in local attire, smart casual or formal wear.

The hotel’s website said today: “Due to unforeseen circumstances, the hotel’s internet and telephone lines are currently disconnected until further notice.” A spokesman for the hotel did not immediately respond to a request tonight for a comment about the detained guests.

© 2017 The New York Times Company