US envoy slams Muslim world for not condemning China's
mass-incarceration of Uighurs
Sam Brownback, ambassador at large for international religious freedom, said he is "disappointed" by the response of majority-Muslim states, The Guardian reported.
Brownback said the states were perhaps wary to bring attention to their own rights record.
US lawmakers have pressured the Trump administration to impose sanctions on China but Brownback refused to say whether these are seriously being considered.
China is facing increasing international condemnation for its policies in the northwest region of Xinjiang, where as many as one million Uighurs and other mostly Muslim minorities are being held in a vast network of internment camps.
But Washington's closest allies and big players in the region - Saudi Arabia, the UAE and Egypt - have been quiet on the issue. Turkey is one of the region's few voices willing to risk its economic relationship with China by expressing support for the Uighur cause.
Saudi's Crown Prince Mohamed bin Salman, in particular, has been criticised for putting Riyadh's relationship with Beijing about the rights of the Muslim minority.
When the crown prince met with Chinese President Xi Jinping in February he defended China's "right" to undertake "anti-terrorism" and "de-extremism" measures.
The Saudi-backed Organisation of Islamic Cooperation (OIC) passed a resolution in March praising China for "providing care to its Muslim citizens".
Brownback, in his interview with The Guardian, said that unless China is stopped by the international community, it could push its oppressive systems out to other "authoritarian regimes".
"I have been disappointed that more Islamic countries have not spoken out. I know the Chinese have been threatening them and but you don’t back down to somebody that does that," he said.
Explainer: China's persecution of Uighur Muslims
Browback mentioned that the US had been in discussion with Saudi Arabia on the issue.
"I think as more information gets out and particularly as it gets out to the population in some of these places that you'll see more of their governments act and react," he said.
A Guardian investigation last month revealed that China had completely - or almost completely - destroyed at least 15 mosques in Uighur Muslim-majority Xinjiang over the past three years.
Following a flare-up in violence in 2014, Chinese authorities rolled out various draconian security measures in Xinjiang - from banning long beards and headscarves to placing up to a million residents in detention camps.
Those free from detention are said to live in what is essentially a testing ground for the world's most sophisticated high-tech surveillance methods.
Muslims in Xinjiang are forced not to fast during the Muslim holy month of Ramadan and have allegedly been forced to drink alcohol and eat pork - both forbidden in Islam - in internment camps.
Rights groups and former inmates see the measures as part of a campaign to forcefully assimilate Uighurs and other minorities into the country's majority ethnic Han society, diluting their unique cultures and religious beliefs.
Agencies contributed to this report.
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