On a quiet street in the ancient Silk Road city of Kashgar, a house lies empty, padlocked from the outside, the family who lived there gone.

The father was detained in February; three months later the mother was also taken away by authorities. They had allegedly shared extremist Islamist content on their mobile phones, family friends said.

Despite protests from relatives, two of their children, aged 18 and 15, were then detained and their younger two, aged seven and nine, were sent to a state welfare centre. “The grandfather even wept, but the authorities would not let him keep his grandchildren,” recalled an acquaintance.

The family had fallen foul of an anti-terror drive conducted by Beijing, which has forcibly separated families, sending thousands of children to de facto orphanages, according to Uighurs interviewed in China and abroad by the Financial Times.

Since the annexation of Xinjiang in 1950, Beijing has had a troubled relationship with the Uighurs, a Muslim Turkic ethnic group.

As the Trump administration struggles to reunite migrants and their children forcibly separated at the US border, China has been separating families on a far larger scale as part of a rapidly intensifying security campaign. The campaign has put the region on lockdown, forbidding Uighurs from travelling and putting them under high-tech digital and physical surveillance.

China has been imprisoning Uighurs in extralegal detention centres in the name of combating terrorism since 2016. China denies that such centres exist, rejecting efforts by western countries to discuss Xinjiang, according to two diplomats.

The number of detentions has grown rapidly; in April, Laura Stone, the US acting deputy assistant secretary for east Asian and Pacific affairs, said the number of Uighurs detained was “at the very least in the tens of thousands”.

The widening scale of the detentions means it is increasingly common for entire extended families to be separated from their children. The younger children are then sent to “child welfare guidance centres” while older children are sometimes sent to state-run vocational institutes, according to residents in Urumqi, Xinjiang’s capital, and Kashgar.

“If both parents are in jail, the child will be sent to a re-education centre for ‘special children’,” said a former teacher in one of the re-education centres. “The child is forbidden to go to school with the normal children because the parents have a political problem.”

In early 2017, Xinjiang began building dozens of these welfare centres, according to public tenders issued by local county governments and local state media reports. The orphanages are being built under a new “five guarantees” policy begun in 2017 that aims to provide orphans with state-sponsored care until they turn 18.

The centres are usually massive in scale, even when located in remote areas. In Yumin county, with a population of 50,000, authorities recently broke ground on a 3,000 sq m centre at a cost of Rmb9.8m ($1.5m). One county in Kashgar built 18 new orphanages in 2017 alone, according to local media.

Not all children are sent to welfare centres, say Xinjiang residents. The rapid escalation of detentions has left local governments unprepared to manage the thousands of children needing care. Some board at existing state-run schools. Older children can be sent to vocational schools, a practice that has existed in China, albeit on a very small scale, for years.

“There has been a big readjustment within the educational system here because of the training schools,” said a retired government official in Kashgar surnamed Dong, employing a common euphemism for the detention centres. “[The children] eat, sleep and learn on the government’s expense, though I would not advise you to send your own children there. It is really all just the children of Uighurs.”

Mutelip (a pseudonym), an Uighur living in the US, had two cousins aged 10 and 12 taken away by government officials and sent to an unspecified school on a state scholarship last April. His grandparents cut off communication with him, fearing punishment for communicating with someone abroad.

“My grandparents tried to take [my cousins] in, but the government wouldn’t allow it. Another uncle of mine was sent to the detention camps after he objected [to the cousins being taken away],” said Mutelip. By his count, he has 86 relatives who have been sent to prison or re-education camps across the region.

As detentions increase, Uighur parents living outside China face an impossible choice: return home and face certain imprisonment or remain abroad, unable to determine what has happened to their children in Xinjiang. Digital and physical surveillance makes contact with family and friends there near impossible.

“I dream of being with my daughter. Then I dream I am in Urumqi and the police are coming to my home and I’m afraid they will take me to prison,” said Tahir Imin, a Uighur academic who left behind a seven-year-old daughter in 2016 to pursue a masters degree in Israel. He is now a political refugee in the US.

Last June, Mr Imin’s wife asked for a divorce, which he granted, after she was repeatedly harassed by local security forces in Urumqi for her relationship with Mr Imin.

Earlier this year, friends in Xinjiang told Mr Imin that his entire extended family had been detained or imprisoned, but they did not provide details for fear that their conversations were being monitored and they would be punished. Mr Imin is unclear about what happened to his daughter. Shortly before cutting off contact in January, his daughter told him to stop contacting his family.

The words cut deep, but he believes they were sent to him under psychological pressure and duress. “She loves me very much,” said Mr Imin. “She knows everything.”

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