The guards picked out the prettiest girl – a teenager with her head shaved and wearing a simple uniform like all the other prisoners lined up silently outside. Told to confess her ‘crimes’, she insisted she was a reformed person. But she was ordered to remove her clothes – and was then raped repeatedly in front of about 200 men and women who were forced to watch a scene of unimaginable horror.

Yet throughout her torment, the girl did not dare scream in terror or cry out in pain. She had been warned not to react. She knew if she made a sound, relatives might suffer a similar fate.

And if any of those forced to watch shut their eyes, flinched or showed fury, they were dragged to a special room for torture.

This is the vocational skills education centre in Dabancheng in Xinjiang Uighur Autonomous Region

‘She was told not to say anything,’ says Sayragul Sauytbay, who claims she was one of those made to witness the savagery.

‘Anyone who reacted in shock or looked away was punished, since it showed they were not yet obedient and changed psychologically. I lost part of myself having to watch this. I don’t remember how many men raped her because I zoned out in shock. I could not sleep at night and started to become numb inside.’

But now Sauytbay is speaking out about the barbarity she saw inside one of China’s clandestine ‘re-education centres’, which are claimed to hold up to three million members of Muslim ethnic groups from the country’s western regions.

She was forced to work inside one as a teacher – then fled China after learning she was about to be sent back inside as a prisoner. Her testimony offers a unique insight into Beijing’s brutal gulags that have been set up over the past three years.

It comes as horrifying details of China’s repression slowly emerge, with revelations of giant concentration camps, mass roundups and razed mosques in a huge region flooded with security forces, checkpoints and facial recognition cameras.

The crackdown, allegedly to thwart terrorism, is focused on the Uighurs, a minority ethnic group of about 12 million people related to the Turks, but it is also targeting other Muslim groups such as Kazakhs, Tajiks and Uzbeks.

Young Muslims read from official Chinese language textbooks in classrooms at the Hotan Vocational Education and Training Center in Hotan, Xinjiang, northwest China

Sauytbay compares the Chinese bid to crush traditional cultures in the Xinjiang region to Nazi efforts to eradicate the Jews, with use of mass surveillance, concentration camps, forced marriage, secret medical procedures, sterilisation and torture.

‘Perhaps it is becoming even worse than the Nazis because they can combine the latest technology such as 24-hour surveillance everywhere with the most primitive methods of torture,’ she tells me.

Inside the camp, this was carried out in a feared ‘black room’ – the only place without cameras to monitor everyone – where devices ranged from electrocution equipment to batons, stun guns and a hideous seat studded with sharp nails.

‘There was constant screaming from there at night,’ says Sauytbay, 43. ‘Sometimes people were dumped back in class badly beaten, or with their nails torn out or blood all over their bottoms and thighs. Others never came back, so I guess they died.’

She was sent to the room herself after an 84-year-old woman was brought into the camp and, seeing Sauytbay, hugged her and begged for help. ‘This woman was held on suspicion of contacting people abroad – but she was an elderly shepherd from the mountains who had never had a mobile phone.

These Muslim school children in Akto, south of Kashgar are kept under constant surveillance by the Chinese state

‘I was taken to the black room and beaten all over my body with electrical stun sticks, then starved for two days. They kept asking me what I had told the old lady.’

After her escape from China, followed by a court battle in Kazakhstan to resist being returned into Beijing’s clutches, Sauytbay has found refuge with her husband Uali and their two children in a quiet coastal town in southern Sweden.

But this brave Kazakh woman, who trained as a doctor then ran five schools before the clampdown, remains haunted by hideous memories. ‘The worse thing was all those people not allowed to speak but pleading with me through their eyes for help,’ she says.

Her claims are highly disturbing. Although impossible to verify, they dovetail with accounts given by the tiny handful of others free to bear witness. Another woman last year spoke of beatings, electrocution and being forced to take strong drugs.

Human rights groups have compiled reports detailing torture, and this month activists published a map of nearly 500 camps and prisons used for detentions. US government officials allege they hold between a million and three million people.

Sauytbay tells me her horrifying story in her new home. She broke down just once – so upset she had to leave the room – when I asked about her childhood.

A day in the camp 6am Wake up. 6-7am Breakfast of watery rice or vegetable soup with small piece of bread. 7-9am Lectures based on placards stating ‘I am Chinese’, ‘I am proud of being Chinese’ and ‘Long live the Communist Party’. The prisoners repeatedly chant phrases. 9-11am Repeat of same lecture and chants. 11-noon Mantras, with inmates repeating phrases such as ‘I would sacrifice my life for the Communist Party’. Noon-2pm Lunch. Same as breakfast. 2-4pm Patriotic songs such as ‘Without the Communist Party, there would be no new China’. 4-6pm Self-evaluation to confess ‘crimes’. 6-8pm Dinner. Same as breakfast and lunch. 8-10pm Prisoners have to reflect on their ‘sins’ while standing against a concrete wall with their arms raised. 10pm-midnight More self-evaluation, based on reflections. Midnight-1am Stand still. 1-6am Sleep on their right-hand side. Advertisement

‘Sometimes I try to remember the old way of life but it becomes overwhelming,’ she says after resuming the interview. ‘We had no advanced technology like today but it was such a happy time.’

Her father ran a school and she was raised with three siblings in a rural area, filled with farm animals and fruit trees. Then tides of Han Chinese people began arriving in the 1990s, taking land and mining minerals in the mountains.

‘It was a gradual takeover,’ recalls Sauytbay. ‘They said they wanted to modernise Xinjiang. But this was our land, our culture, our people – it was like a foreign force from Europe taking over a country in Africa.

‘At the start there was no hatred. But then they built all these factories and blew up our mountains. The river stopped flowing, which meant we had to walk a long way for our water, and snow turned black on the surface in winter.’

Official data shows the Beijing government invested heavily in the region while moving in millions of people. Han Chinese now comprise two in every five people in Xinjiang, a seven-fold rise since the region was annexed in 1949.

As in Tibet, this takeover was backed by a Communist Party drive to wipe out local cultures, arts and religion. Working in schools, Sauytbay saw this first-hand with children forced to speak Chinese rather than their traditional language.

Yet she was mystified when her son, then three, started refusing to go to kindergarten – until he said his mouth was being taped up all day because he spoke only Kazakh. ‘I was heartbroken – my child was being abused at his school.’

After an eruption of anti-government protests and deadly terror attacks, President Xi Jinping demanded an all-out ‘struggle against terrorism, infiltration and separatism’ with ‘absolutely no mercy’, according to leaked documents published last week. Sauytbay was forced to teach in one of the indoctrination camps after her husband and children fled China – they escaped just weeks before all passports were confiscated.

She could not join them because public servants had already been made to hand in passports – and feared for her future after security forces began rounding up people, taking samples of DNA and installing cameras everywhere.

Former camp inmate Sayragul Sauytbay, pictured, said she witnessed inmates of a Chinese concentration camp raped repeatedly in front of 200 men and women

In January 2017, she was arrested, ordered to make her family return home and warned not to talk about her questioning. Similar interrogations continued – often through the night – almost weekly for the next ten months. She dared not tell anyone what was happening, not even her family. ‘There were cameras everywhere in the streets and no one talked to each other, even at home, since everything was bugged and we were told to report any suspicious activities.’

Then she was ordered to go to an address where four armed men put a black bag over her head and drove her about four hours to a mountain camp. ‘I was so filled with dread,’ she says. ‘I thought this would be my final destination.’

Upon arrival, Sauytbay was stripped of her possessions, handed a military-style uniform, told she would be a teacher and forced to sign a document accepting the death penalty if she broke rules that forbade laughing, crying or talking to prisoners. She was given her own barren room, with just a thin plastic mattress on the floor – still better than the shackled prisoners who were allocated one square metre each and forced to sleep on their right side crammed against each other in concrete cells.

‘This was just the rule,’ she says. ‘There was no reason why they had to sleep on their right. It was another form of torture – but if you moved you were taken to the black room.’

The next morning she started teaching classes of about 60 captives who had to chant praise for China, sing songs of loyalty to the Communist Party and confess ‘crimes’. ‘They would write anything that fitted the suspicions of the government. So if they were religious, for instance, they might say they had talked to their family about Allah.’

Even people who were observant Muslims were forced to eat pork on Fridays. ‘The food was very poor – I wouldn’t even call it food, just watery soup and bread,’ says Sauytbay. ‘But if you did not eat it you went to the black room.’

She says teachers and prisoners were terrified of the guards, claiming they were like ‘wild dogs with unlimited power’ who would grab women and rape them. ‘When the officers picked out the prettiest girls, you knew what was going to happen.’

Sauytbay also says they used enforced medication: ‘It was not secret but all done openly with whole rooms injected at once.’

She recognised some of the drugs from her medical training. ‘I was told the names by a nurse, who said it was to prevent Aids and disease. But I think it was to sterilise people and stop them having children.’ These chilling claims cannot be confirmed, but Sauytbay says they made women stop having periods, while a man held in another camp said he was left impotent.

Her allegations tie in with other reports of children from minority groups sent to a network of state-run orphanages set up in Xinjiang, while Sauytbay also says wives of incarcerated men were being forced to remarry Chinese men.

She estimates her camp held about 2,500 people, including children as young as 13, although she does not know its exact location. She was not allowed to leave during four months there. Her nightmare in camp ended in February last year when she was told to return home and never discuss what she had seen. She had a black bag put over her head before being driven to her home town.

But days later she was arrested and accused of being a double agent because her family was still abroad. Police told her she needed up to three years of ‘re-education’ and made her sign a document agreeing with their decision.

She fled after being sent home first to write a report on the running of her schools. ‘I knew I would not come out alive after what I had seen in the camps,’ she maintains. ‘I thought if I was going to die anyway, I might as well die trying to see my family again.’

Aware that she was being monitored, Sauytbay went home, cooked dinner – then escaped through a back window, reaching the nearby border after two terrifying taxi rides. ‘China has an agenda of “One Nation, One Ethnicity” and will not accept any resistance to achieving its goals,’ she says. ‘But they have given up their humanity.

‘The world needs to look past the economic opportunities and see the hidden agenda, the terror, the way the Communist Party is oppressing people.

‘The free world must raise voices against the tyranny that I’ve seen of the Chinese regime.’