A disturbing video shows hundreds of blindfolded prisoners being led from a train in China with their heads shaved.
The drone footage, posted online anonymously last week, shows hundreds of men, mostly dressed in purple and orange vests with the words "Kashgar Detention Center" printed on them.
They can be seen seating in rows on the ground of what seems to be a large courtyard outside a train station.
With their heads shaved and their hands bound behind their backs, all of the men wear black blindfolds over their eyes while dozens of police officers surround them.
It is unclear why the men are being held by authorities.
Some of the prisoners are then filmed as police officers escort them outside the station.
The video has raised concerns over the treatment of on Muslim Uyghurs in the far western region of Xinjiang.
War on Fear, the YouTube channel which uploaded the video, says the scene relates to "the long-term suppression of human rights and fundamental freedoms by the Chinese government in the Xinjiang Uygur Autonomous Region".
Prisoners in China are regularly transported with handcuffs and wearing blindfolds, The Guardian reports.
Authorities in Xinjiang released a statement to CNN saying: "Cracking down on crimes in accordance with law is the common practice of all countries.
"Xinjiang's crackdown on crimes has never been linked to ethnicities or religions.
"Transporting inmates by judicial authorities (is related) to normal judicial activities."
Muslim Uyghurs are a minority in China but the biggest group in Xinjiang, The Atlantic reports.
China has been criticised internationally for its anti-terrorism campaign which has seen more than one million ethnic Uyghurs and other Muslim minorities in internment and political re-education camps.
About 10 percent of the Uyghur population in the region is currently locked up, according to NBC News .
