- Saudis accuse Iran-backed Hezbollah of firing missile at capital Riyadh: 'An act of war'
- An ambitious heir and a bitter family feud are shaking up Saudi Arabia
- How Israel can avoid war with Iran and Hezbollah - for now
Trump, who has cultivated much warmer ties with Riyadh than his predecessor Barack Obama, tweeted on Monday that he has "great confidence in King Salman and the Crown Prince of Saudi Arabia" following the mass arrests, which was the biggest anti-corruption purge of the kingdom's affluent elite in its modern history.
Trump also tweeted that "they know exactly what they are doing," adding: "Some of those they are harshly treating have been 'milking' their country for years."
Among those arrested were billionaire investor Alwaleed bin Talal who is one of the kingdom's most prominent businessmen.
The purge is the latest in a series of dramatic steps by Crown Prince Mohammed bin Salman to assert Saudi influence internationally and amass more power for himself at home.
Trump's first trip abroad as president was to Saudi Arabia where King Salman gave him a remarkably warm greeting. U.S.-Saudi ties had been strained under the Obama administration, whom they felt considered Riyadh's alliance with Washington less important than negotiating the Iran nuclear deal.