Former detainees allege they were subjected to intense political indoctrination, forced labor, torture, and even sexual abuse. China vehemently denies allegations of human rights abuses, insisting the camps are voluntary "vocational training centers" designed to stamp out religious extremism and terrorism.

Tuhan said she fears what will happen to her and her family if they're forced to return.

"All these past years, life was difficult ... But what is happening now is the worst," she said, referring to the Taliban takeover. "It is just a matter of time before (the Taliban) find out that we are Uyghurs. Our lives are in danger."

"China refugee"

Tuhan was just 7 years old when she and her parents fled Yarkand, an oasis on the ancient Silk Road near the Chinese border with Afghanistan.

Many of them fled China after the Communist Party took control of Xinjiang in 1949. Some -- like Tuhan -- migrated in the mid-1970s, during the chaos of the last years of the Cultural Revolution, crossing mountain passes in the south of Xinjiang to seek refuge, Roberts said.

Many of the Uyghurs now hold Afghan citizenship, but their identification cards still identify them as Chinese refugees -- including second generation immigrants, according to an ID photo shared with CNN and accounts of two Uyghurs.

Abdul Aziz Naseri, whose parents fled Xinjiang in 1976, said his ID still identifies him as a "China refugee," even though he was born in Kabul.

Naseri, who now lives in Turkey, said he has collected the names of more than 100 Uyghur families who want to flee Afghanistan.

"They're afraid from China, because the Taliban was dealing with China behind the door. And they are afraid to (be) sent back to China," he said.

A "good friend"

There's reason for Uyghurs in Afghanistan to be worried, say experts.

In July, a Taliban delegation paid a high-profile visit to Tianjin, where they met with Chinese Foreign Minister Wang Yi.

Wang called the Taliban "an important military and political force in Afghanistan" and declared that they would play "an important role in the country's peace, reconciliation and reconstruction process."

"China is a very important and strong country in our neighborhood, and we have had very positive and good relations with China in the past," Zabihullah Mujahid said. "We want to make these relations even stronger and want to improve the mutual trust level."

Roberts said Uyghurs' fears the Taliban could deport them to China to gain more favor with Beijing were legitimate.

"(The Taliban) have a lot of reasons to try to ingratiate Beijing in terms of gaining international recognition, in terms of getting financial assistance at the time when most of the international community is not giving them financial assistance," he said.

Tuhan's concern over potentially being forced to return to China is deepened by Beijing's increasingly aggressive efforts in recent years to bring overseas Uyghurs back to Xinjiang, including from Muslim countries.

In a report published in June, the Uyghur Human Rights Project said there were least 395 cases of Uyghurs being deported, extradited, or rendered back to China from countries across the world since 1997.

In a statement to CNN, China's Foreign Ministry called the Uyghur Human Rights Project an "outright anti-China separatist organization."

"The so-called data and reports released by them have no impartiality and credibility, and are not worth refuting at all," it said.

Cracking down on militants

The Chinese government has a long history of engaging with the Taliban, dating back to the late 1990s, when the militant group last controlled Afghanistan.

During his July meeting with Taliban officials in Tianjin, Wang, the Chinese foreign minister, said ETIM "poses a direct threat to China's state security and territory integrity."

But experts say there is little independent evidence to confirm China's claims of ETIM's size, capabilities and influence -- and there are doubts that it still exists today.

ETIM started as a small group of Uyghurs who came to Taliban-ruled Afghanistan in 1998 with the intent to establish an insurgency against Chinese rule, according to Roberts.

"They've been very prolific in terms of producing videos threatening Beijing, but there's no evidence of them being able to carry out any attacks inside China," Roberts said.

But the Chinese government has continued to use the existence of the TIP -- which Beijing still refers to by the name ETIM -- to highlight the threat of terrorism and justify its ongoing crackdown in Xinjiang, said experts and Uyghur activists.

"Why send a friend?"

Now in her early 50s, Tuhan lives in northern Afghanistan, making a living by tailoring people's clothes, while her children do odd jobs, like painting neighbors' houses, for whatever money they can get.

But even regular people like her could find themselves swept up in Beijing's campaign against terror groups.

Roberts said it is unclear that TIP has a significant presence in Afghanistan, although a small number of its members are believed to be living in the country. If the Taliban were to deport anyone to China, it would most likely be ordinary Uyghurs rather than the TIP members they have had long-term relations with, he said.

"If they want to show Beijing they were being receptive to its demands (for repatriation), why send a friend they know when they could just send any random Uyghurs in Afghanistan and suggest they are a threat to Beijing?" Roberts said.

Despite having lived for decades in Afghanistan, the Uyghurs are considered outsiders, and unlike thousands of people airlifted to safety by the US and its allies, they have no country to help negotiate their exit.

"They don't really have anybody to advocate on their behalf, to help them get out of the country," Roberts said.

Tuhan said she and her family don't even have passports, so they have limited options to leave Afghanistan, even if another country was willing to take them.

"They don't give passport for free, and we can't afford it. But now they have stopped issuing the passports anyway," she said.

"It has been 45 years since we fled here. We have grown old without seeing a good day," she said. "Hopefully our kids could have a better life. That's all we want. We just want to be saved from this oppression."