Now, women in China's so-called re-education camps have been systematically raped and tortured. That's according to first-hand accounts obtained by the BBC. It's estimated more than a million men and women have been detained in the camps in China's northwest Xinjiang region. China claims the camps are re-education centers to de-radicalize Uyghurs and other Muslim minorities.
Our correspondent Matthew Hill has spoken to several former detainees and workers. and you may find some of their accounts distressing. Tersenai Zaiwudun is reliving a story she can barely bring herself to tell.
She was held at one of Xinjiang's so-called re-education camps. These satellite images show the site where Tersenai says she was held, sharing a cell with 13 other women with a bucket for a toilet. And she's haunted by one image, masked men coming down a camp corridor.
like this one after midnight. They were three men. Not one, but three. They did whatever evil their mind could think of and they didn't spare any part of my body, biting it to the extent that it was disgusting to look at. They didn't just rape.
They were barbaric. They had bitten all over my body. The US have granted her safe refuge after investigating her claims. She's waived her right to anonymity and now feels free to speak out about the full extent of the abuse she says she suffered.
They had an electric baton. I didn't know what it was. It was pushed into my private parts and I was tormented with electric shocks.
It's estimated over a million Uyghurs and other Muslims are held in the camps. These never-before-broadcast pictures were filmed secretly in a camp under construction and published by a magazine on religious liberty. We've interviewed a former guard and seen his Chinese police documents. He's the first ever to come forward and the risk of him speaking to the BBC is so great, we've reconstructed the interview with an actor.
Those who were taken inside, were locked in a cell which holds 8 to 16 inmates. There were cameras watching them all the time and there were books about Xi Jinping. They had to study the book and memorize them in Chinese.
If they fell, the punishment was severe. Many former camp inmates flee to Istanbul. Some talk of having to choose between punishment or being complicit in these crimes. I worked six months as a cleaning worker for the women.
Han Chinese men would pay money to have their pick of the pretty young inmates. This was the first time Gulzira has told anyone the full extent of what she says she was forced to do. My job is to remove their clothes and then handcuff them on their beds so they cannot move. We can't say if the rape is approved by the camp commanders or even by those more senior, but the accounts of the many women I've spoken to include gang rape in public and are similar in brutality. The Uyghur Rights Group that helped Tess and I get to America say their false stories don't emerge until later.
Survivors of the camps have told of horrific tortures. Very often sexual abuse, however, is told in less detail. It's traumatic to remember. And women are often afraid of bringing shame to their own family members. The Chinese government said in a statement of the Xinjiang camps offered vocational and educational training to tackle extremism and terrorism.
It did not address directly the accusations of rape and torture, but it added the Chinese government attaches great importance to women's rights. Lies and absurd accusations, including mass detention, do not hold water. It is very obvious their goal is to destroy everyone and everyone knows it.
These women are done. Much of the testimony of the women, like Terse and I have spoken to, is too disturbing to broadcast. But it's important, they say, that the world knows what's happened to them.
Matthew Hill, BBC News. You can read the BBC's exclusive report on the Uyghurs with more eyewitness accounts and analysis on our website. Just go to the usual place, bbc.com, and it's in the World News China section.