Kabul, Afghanistan - Isreal Ahmet, an ethnic Uighur who immigrated to Afghanistan from western China, lived and worked in Kabul for more than a decade before being detained and deported by Afghanistan's National Directorate of Security (NDS) last summer.

Ahmet, who lived in a meagre, mud-brick house, was described as an honest businessman by those who know him.

An NDS official - speaking on condition of anonymity because he wasn't authorised to talk to the media - told Al Jazeera that Ahmet was detained for lacking legal documentation and carrying counterfeit money. He was held in a jail cell with more than two dozen other Chinese Uighurs, including women and children.

Flagged as a spy, Ahmet was quickly escorted to the Kabul International Airport, where Chinese officials were waiting for him. He boarded a plane and has not been heard from since.

Eleven other Uighur men sharing a cell with Ahmet were also sent back to China, according to the NDS official, adding that six women and 12 children in another cell had refused to go. The whereabouts of these women and children are currently unknown.

"Some [of the detainees] were spies, some were [potential] suicide attackers and some illegally entered the country," said the NDS official.

The Uighurs: External Exile

In recent weeks, five more Uighurs were detained in Afghanistan, the official said, however, all five managed to "escape".

China's 'Strike Hard' crackdown

Most Uighurs - an ethnic minority that practices Islam - live in the Xinjiang Uighur Autonomous Region in western China, which has a short border with Afghanistan.

Many have fled China in recent years to escape the government's crackdown on practising Muslims in Xinjiang, which has included restrictions on fasting during Ramadan and wearing the veil.

The deportation of Ahmet and other Uighurs in Afghanistan occurred during China's ongoing "Strike Hard" campaign, which was launched the day after a deadly attack on a market killed dozens of people in Urumqi, the Xinjiang region's capital, last May.

The secretive deportations of Uighurs living in Afghanistan highlight China's growing influence on its neighbours, who in recent years have come under pressure to hand over members of the persecuted minority living within their borders.

William Nee, a China researcher at Amnesty International, said the Chinese government has exerted diplomatic pressure on Thailand, Turkey and other countries to repatriate Uighurs.

Last November, China criticised Turkey for sheltering 200 Uighurs who had been rescued from human smugglers in Thailand. In 2009, China signed trade deals with Cambodia that were collectively worth about $1bn - two days after Cambodia deported 20 Uighurs to China.

During Afghan President Ashraf Ghani's visit to China last October, Chinese President Xi Jinping pledged hundreds of millions of dollars in assistance, training and scholarships. Most importantly, China - an ally of Pakistan - offered to help the Afghan government in its peace talks with the Taliban, which enjoys support in parts of Pakistan's tribal areas.

In return, Ghani reassured Xi of Afghanistan's support for China's fight against the East Turkestan Islamic Movement (ETIM), a Uighur separatist group that China blames for a number of deadly attacks in the country over the past decade.

"No written agreements have been made between the two countries, just verbal," said Sultan Ahmad, the former Afghan ambassador to China who now serves as a director at the Ministry of Foreign Affairs in Kabul.

"We see this as a window of opportunity. China is worried about their own security, and they need cooperation from all countries. They can help us with the reconstruction of Afghanistan and our relationship with Pakistan, with whom they share close relations. For us, it is very important to have a relationship with the Taliban and Pakistan."

Acting NDS Director Rahmatullah Nabil, who visited Beijing just before Ghani's trip, declined to comment for this article.

'We're warning Beijing'

During Afghanistan's rule by the Taliban, about a dozen ETIM fighters were based in Kabul under the command of the Islamic Movement of Uzbekistan (IMU), according to Waheed Mozhdah, a political analyst who served as an official in the foreign ministry at the time. Taliban and Chinese officials met several times about the issue.

China imposes Uighur restrictions

After the US-led invasion of Afghanistan in 2001, ETIM fighters crossed the border into Pakistan.

Today, about 200 ETIM members are believed to reside in Taliban-controlled areas of Afghanistan's Kunar province and Pakistan's tribal belt, according to Mozhdah.

The number of attacks in China attributed to Uighur separatists has increased in recent years. "Yet, there is still no evidence that the things that have happened have any international ties," said cultural anthropologist Sean Roberts, a professor at George Washington University.

"In fact, they are still very rudimentary type of attacks that look to be more home-grown."

Last month, reports emerged of a Taliban delegation in Beijing holding talks with Chinese officials. Afghan Taliban spokesman Zabihullah Mujahid declined to comment, saying top leaders had not yet confirmed the news.

He also said he didn't have information regarding the treatment of Uighurs in China, or of those detained by the Afghan government.

"Before the American invasion, there were Uighurs here, but now we don't know," Mujahid said.

"For China, Central Asian states and our neighbours, we first want to make our strategy clear. We want them to understand why we are fighting here. And then, if there is an issue regarding the repression and killing of Uighurs in China, we would likely raise that subject during our talks with them."

The issue has not gone unnoticed by other armed groups in the region, who have threatened China for its policies in Xinjiang.

In November 2014, the Tehreek-e-Taliban Pakistan Jamaat-ul Ahrar - an offshoot of the Pakistani Taliban - published an article in its official magazine, which said: "We're warning Beijing to stop killing Uighurs. If you don't change your anti-Muslim policies, soon the mujahideen will target you."

Restricting Islamic practices

Meanwhile, what is happening within China's borders is worrisome, said Amnesty's Nee.

The public wearing of veils, beards and T-shirts featuring the Islamic crescent has been banned in many cities across Xinjiang. Students have been restricted from observing Ramadan, and there have been reports of force-feeding those who insist on fasting. Others have been disciplined for openly worshipping or downloading unsanctioned material.

Last month, local authorities in Urumqi banned wearing the veil in public. Meanwhile, the number of people whom the Chinese government has sentenced to death has risen, said Nee.

"Religious extremism is being lumped together with violent terrorism. For example, any religious practice [that is] not state-sanctioned … then you could be characterised as participating in religious extremism," Nee explained.

"One concern for Amnesty International is that normal migrants will be repatriated to China under the framework of anti-terrorism - people who may just be fleeing for better economic conditions. Maybe they are first going to Afghanistan before going to United States or Europe, and they are hauled back to China."

China's Ambassador to Afghanistan Deng Xijun declined requests for comment.

Little information

Bo Schack, the United Nations refugee agency's (UNHCR) representative in Afghanistan, told Al Jazeera he has little information about deported Uighurs.

"There is currently no one in detention. We believe some were returned to their country," he said.

"There are rules under the international convention [prohibiting the deportation of people to countries where their lives may be at risk]. But Afghanistan has no laws in place."

Schack also said UNHCR had no record of female and children Uighurs being detained, which contradicts other accounts.

Under international refugee law, the principle of non-refoulement prohibits states from returning refugees to a place where their lives or freedom is under threat. Yet, in the absence of an extradition treaty, activists say Afghanistan has discretion on whether to comply with China's request.