China is detaining members of the Uyghur ethnic group in almost 500 camps and prisons, according to rights activists.
They also believe Beijing could be detaining far more than the one million Muslims thought to be held in the region China calls Xinjiang.
The East Turkistan National Awakening Movement, a Washington-based group that seeks independence for the region, provided the locations of 182 suspected camps where Uyghurs are allegedly pressured into turning their back on their culture.
Having studied imagery from Google Earth, the group also said it had identified a further 209 possible prisons and 74 labor camps.
“In large part these have not been previously identified, so we could be talking about far greater numbers” of prisoners, Kyle Olbert, the group’s director of operations said, reported AFP.
“We are concerned that there may be more facilities that we have not been able to identify,” he told reporters at a news briefing in Washington.
Rights groups believe China is holding more than one million Uyghurs and people from other Muslim ethnic groups in facilities likened to Nazi Germany’s concentration camps.
Randall Schriver, a top Pentagon official, said earlier this year that the figure was probably nearer three million.
This has included trying to prevent them praying and forcing them to eat pork.
Olbert called China’s actions “genocide by incarceration.”
He said there is the real possibility that these people could be held indefinitely.
“If they were just to keep everyone imprisoned and let them die off naturally, perhaps the world might not notice. I think that’s what China is banking on,” he said.
China says it is only providing vocational training and coaxing Muslims away from extremism that Beijing blames for violence in Xinjiang’s capital Urumqi that killed hundreds, many of whom were Han Chinese.