The Uighurs, a mostly Muslim ethnic minority living in Xinjiang, are watched by tens of thousands of facial recognition cameras, forced to download surveillance apps on their phones, and not allowed to exhibit Muslim markers like eating halal food or growing a beard.
A growing number of Muslim-dominant countries, notably Turkey , have spoken up against the issue to Beijing's ire. But Saudi Arabia, in an effort to boost trade ties, has appeared to turn a blind eye to it.
According to China's state-run Xinhua news agency, Crown Prince Mohammed on Friday told Chinese President Xi Jinping: "We respect and support China's rights to take counter-terrorism and de-extremism measures to safeguard national security." He did not mention Xinjiang or Uighurs by name.
Crown Prince Mohammed's comments came during his trade trip to Beijing this week, during which Saudi Arabia and China signed 35 economic-cooperation agreements worth a total of $28 billion at a joint investment forum, according to Saudi state news agency SPA.
Why the crown princes approval matters
The crown prince's implicit support of China's crackdown in Xinjiang is significant considering his role in the Muslim world.
His father, King Salman, is referred to as the Custodian of the Two Holy Mosques a deferential title used to acknowledge his responsibility of the two holy cities of Mecca and Medina.
Earlier this week an unnamed Beijing-based diplomat told Reuters that China was keen to head off criticism from Muslim countries about its internment camps.
China also appeared to turn a blind eye to Saudi Arabia's human rights record. Crown Prince Mohammed is widely believed to be responsible for the brutal killing of journalist Jamal Khashoggi , who died at the hands of Saudi agents in the kingdom's consulate in Istanbul last October.
US Senators, and reportedly the CIA, have already pointed the finger at him. But according to China's state-run CCTV news channel , Xi told the crown prince on Friday that China "opposes any moves to interfere in Saudi Arabia's internal affairs."
SEE ALSO: Relatives of China's oppressed Muslim minority are getting blocked online by their own family members, who are terrified to even tell them how bad their lives are