Riyadh: 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 six-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, reports the Telegraph.

In a shaky video that appears from its metadata to have been shot early on Monday morning in the hotel’s Ballroom B, people can be seen lying on mats covered with brightly coloured blankets in floral motifs while guards in dark uniforms are visible in the background.

In a corner stands a rifle, which appears to be an American standard military-issue M4, its civilian variant or a copycat.

Saudi Arabia finds itself in the midst of a crackdown on corruption that began on 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 Monday, American officials tracking the situation said that has many as 500 people had been rounded up in the sweep.

The country’s attorney general, Sheikh Saud al-Mujeb, said on Monday 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.