Pakistan-trained Eastern Turkestan Islamic Movement (ETIM) militants operating in China's Xinjiang Uighur Autonomous Region have emerged as a major threat to Beijing' national security, according to Defence experts.

The increased threat perception comes at a time when Chinese counter-terrorism efforts have invited criticism from human rights outfits and western governments. China has allegedly detained a large number of Uighur Muslim people in "re-integration and re-education centres" to eliminate extremism. The UN Committee on the Elimination of Racial Discrimination claimed that two million Uighur and other Muslims are kept in contentious detention centres.

The Afghan side is also aware of these concerns, said a defence expert to Hindustan Times on conditions of anonymity. "Some 50 to 60 ETIM fighters have been captured and handed over to the Chinese," he added.

The issue of ETIM was formally addressed by Chinese President Xi Jinping when he met his Afghan counterpart Mohammad Ashraf Ghani on June 13.

Why is a minority group a threat to China?

While Muslims account for 1.6 percent of China's total population, the greater concentration of Muslims in Xinjiang, with a significant Uighur population, has been a cause of concern owing to its association with the East Turkestan independence movement and terrorism by ETIM.

The outfit was founded by Hasan Mahsum from Xinjiang in 1997. A year later, Mahsum shifted the headquarter to Kabul under the Taliban's regime in Afganistan. The Chinese government claim that Mahsum met leaders of al-Qaeda and the Taliban including Osama bin Laden in 1999, although Mahsum denied the allegations. He was killed by Pakistani troops in October 2003.

Currently, the ETIM is led by Abdul Haq, who was also a member of Al-Qaida's Shura Council as of 2005. The UN Security Council reported that the group's members have increased to about 200 with the recruitment of non-Chinese members to the organisation.

The structure of the organisation has strengthened with regards to its scale, enhanced internal administration, developed weaponry as well as sophisticated equipment and operational capacity, according to the UN Sanctions Committee.

Since the 9/11 attacks, the group has been termed as a terrorist organisation by the European Union, Kyrgyzstan, Kazakhstan, Russia, Unites Arab Emirates, United Kingdom, China, the United States and Pakistan. It's Syrian branch, 'Turkistan Islamic Party' in Syria is active in the Syrian Civil War.

Although the outfit is banned in Pakistan, it continues to have its headquarters in North Waziristan district in Pakistan, bordering Afghanistan. The banned terrorist outfit committed over 200 acts of terrorism, resulting in at least 162 deaths and over 440 injuries between 1990 and 2001, according to a Chinese report published in 2002.

The report also stated that acts of violence including explosions, assassinations, arsons, poisonings, and assaults, with the objective of founding a so-called state of "East Turkistan", have threatened social and security stability in China and neighbouring countries.

The most prominent acts performed by the group include, blowing up of the warehouse of the Urumqi Train Station on 23 May 1998, the armed looting of 247,000 RMB Yuan in Urumqi on 4 February 1999, an explosion in Hetian City, Xinjiang, on 25 March 1999 and violent resistance against arrest in Xinhe County, Xinjiang, on 18 June 1999. These incidents resulted in the deaths of 140 people and injuries to 371 according to the UN Security Council's Al-Qaida Sanctions Committee report.

An attack at a coal mine in 2015 by suspected Uighur militants led to the death of 28 people by the Chinese police in Xinjiang. The aggressive move by the police was taken a month after attackers armed with knives killed 50 civilians including five police officers in Sogan colliery in Aksu province.

Analyst Andrew McGregor stated that the militant group's main complaints are government restrictions on the number of children, the demolition of historical Muslim urban areas and the imposition of equality between men and women "in rights and duties" by the communist regime.

"The Chinese side would like the institutions and structures created over the past 18 years to be preserved, as it feels getting rid of them could lead to anarchy and chaos," the defence expert told HT.